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Sample records for remonte lopatok gtd

  1. Design features of the GTD 8000 and GTD 15000 marine gas turbine engines

    NASA Astrophysics Data System (ADS)

    Romanov, Viktor I.

    1992-06-01

    An account is given of the design features and performance of the GTD 8000 and GTD 15000 marine gas turbines, whose simple-cycle thermodynamic efficiencyis of the order of 34-35 percent. A development history is presented for the component design improvements through which such performance levels were achieved. Attention is given to the counterflow combustor, bearings, and high pressure compressor/turbine spool rotor joint assembly features. These powerplants are suitable for hydrofoil and hovercraft applications.

  2. A GTD analysis of ogive pedestal

    NASA Technical Reports Server (NTRS)

    Lai, Kin-Yue Albert; Burnside, Walter D.

    1987-01-01

    The metal ogive pedestal is claimed to have low radar cross section and low observability features. This study uses the Geometric Theory of Diffraction (GTD) to analyze the pedestal scattering for three cases: direct backscattered field, backscattered field structure, and target/pedestal multiple scattering. This study can be used to evaluate the various ways that the metal conical ogive pedestal can effect the performance of a high quality radar cross section measurement system.

  3. Remontant erosion in desert soils of Tamaulipas, México.

    NASA Astrophysics Data System (ADS)

    Rivera-Ortiz, P.; Andrade-Limas, E.; De la Garza-Requena, F.; Castro-Meza, B.

    2012-04-01

    REMONTANT EROSION IN DESERT SOILS OF TAMAULIPAS MÉXICO Rivera-Ortiz, P.1; Andrade-Limas, E.1; De la Garza-Requena, F.1 and Castro-Meza, B.1 1Facultad de Ingeniería y Ciencias, Universidad Autónoma de Tamaulipas, México The degradation of soil reduces the capacity of soils to produce food and sustain life. Erosion is one of the main types of soil degradation. Hydric erosion of remontant type can occur in soils located close to the channel of a river through the expansion of a gully that begins as a fluvial incision over the ravine of one side of the river. The incision takes place at the point of greatest flow of runoff from areas adjacent to empty into the river. The depth of the incision causes the growth of the gully by collapse to move their heads back, upstream. The soil loss by remontant erosion on land use in agriculture and livestock was estimated in order to understand the evolution of gullies formed by this type of erosion. Through measurements on satellite images and GPS (Global Positioning System) two gullies, developed on alluvial soils which drain into the river Chihue, were studied. The investigation was conducted during 2003 to 2010 period in the municipality of Jaumave, Tamaulipas, in northeastern Mexico. Soil loss in gullies developed by remontant erosion was large and it was caused by soil collapse and drag of soil on the headers. The estimated loss of soil by remontant erosion was 3500 t in the deeper gully during 2010 and nearly 1200 t per year in the period 2003-2009. New sections of gully of about 20 m length, with more than 3 m deep and up to 13 m wide, were formed each year. This degradation has significantly reduced the productive surface of soil that for many years has been used to the cultivation of maize (Zea mays) and beans (Phaseolus vulgaris) as well as pasture production.

  4. NASA solar dynamic ground test demonstration (GTD) program and its application to space nuclear power

    NASA Astrophysics Data System (ADS)

    Harper, William B.; Shaltens, Richard K.

    1993-01-01

    Closed Brayton cycle power conversion systems are readily adaptable to any heat source contemplated for space application. The inert gas working fluid can be used directly in gas-cooled reactors and coupled to a variety of heat sources (reactor, isotope or solar) by a heat exchanger. This point is demonstrated by the incorporation in the NASA 2 kWe Solar Dynamic (SD) Space Power Ground Test Demonstration (GTD) Program of the turboalternator-compressor and recuperator from the Brayton Isotope Power System (BIPS) program. This paper will review the goals and status of the SD GTD Program, initiated in April 1992. The performance of the BIPS isotope-heated system will be compared to the solar-heated GTD system incorporating the BIPS components and the applicability of the GTD test bed to dynamics space nuclear power R&D will be discussed.

  5. Analysis of elliptically polarized cavity backed antennas using a combined FEM/MoM/GTD technique

    NASA Technical Reports Server (NTRS)

    Reddy, C. J.; Deshpande, M. D.; Fralick, D. T.

    1995-01-01

    Radiation pattern prediction analysis of elliptically polarized cavity backed aperture antennas in a finite ground plane is carried out using a combined finite element method (FEM)/method of moments (MoM)/geometrical theory of diffraction (GTD) technique. The magnetic current on the cavity-backed aperture in an infinite ground plane is calculated using the combined FEM/MoM analysis. GTD, including the slope diffraction contribution, is used to calculate the diffracted fields due to both soft and hard polarizations at the edges of the finite ground plane. Numerical results for the radiation patterns of a cavity backed circular spiral microstrip patch antenna excited by a coaxial probe in a finite rectangular ground plane are computed and compared with experimental results.

  6. Simulation of the UT inspection of planar defects using a generic GTD-Kirchhoff approach

    SciTech Connect

    Dorval, Vincent Darmon, Michel Chatillon, Sylvain; Fradkin, Larissa

    2015-03-31

    The modeling of ultrasonic Non Destructive Evaluation often plays an important part in the assessment of detection capabilities or as a help to interpret experiments. The ultrasonic modeling tool of the CIVA platform uses semi-analytical approximations for fast computations. Kirchhoff and GTD are two classical approximations for the modeling of echoes from plane-like defects such as cracks, and they aim at taking into account two different types of physical phenomena. The Kirchhoff approximation is mainly suitable to predict specular reflections from the flaw surface, whereas GTD is dedicated to the modeling of edge diffraction. As a consequence, these two approximations have distinct and complementary validity domains. Choosing between them requires expertise and is problematic in some inspection configurations. The Physical Theory of Diffraction (PTD) was developed based on both Kirchhoff and GTD in order to combine their advantages and overcome their limitations. The theoretical basis for PTD and its integration in the CIVA modeling approach are discussed in this communication. Several results that validate this newly developed model and illustrate its advantages are presented.

  7. Seventy-meter antenna performance predictions: GTD analysis compared with traditional ray-tracing methods

    NASA Technical Reports Server (NTRS)

    Schredder, J. M.

    1988-01-01

    A comparative analysis was performed, using both the Geometrical Theory of Diffraction (GTD) and traditional pathlength error analysis techniques, for predicting RF antenna gain performance and pointing corrections. The NASA/JPL 70 meter antenna with its shaped surface was analyzed for gravity loading over the range of elevation angles. Also analyzed were the effects of lateral and axial displacements of the subreflector. Significant differences were noted between the predictions of the two methods, in the effect of subreflector displacements, and in the optimal subreflector positions to focus a gravity-deformed main reflector. The results are of relevance to future design procedure.

  8. Initial results from the Solar Dynamic (SD) Ground Test Demonstration (GTD) project at NASA Lewis

    NASA Technical Reports Server (NTRS)

    Shaltens, Richard K.; Boyle, Robert V.

    1995-01-01

    A government/industry team designed, built, and tested a 2 kWe solar dynamic space power system in a large thermal/vacuum facility with a simulated sun at the NASA Lewis Research Center. The Lewis facility provides an accurate simulation of temperatures, high vacuum, and solar flux as encountered in low earth orbit. This paper reviews the goals and status of the Solar Dynamic (SD) Ground Test Demonstration (GTD) program and describes the initial testing, including both operational and performance data. This SD technology has the potential as a future power source for the International Space Station Alpha.

  9. Seventy-meter antenna performance predictions: GTD analysis compared with traditional ray-tracing methods

    NASA Astrophysics Data System (ADS)

    Schredder, J. M.

    1988-02-01

    A comparative analysis was performed, using both the Geometrical Theory of Diffraction (GTD) and traditional pathlength error analysis techniques, for predicting RF antenna gain performance and pointing corrections. The NASA/JPL 70 meter antenna with its shaped surface was analyzed for gravity loading over the range of elevation angles. Also analyzed were the effects of lateral and axial displacements of the subreflector. Significant differences were noted between the predictions of the two methods, in the effect of subreflector displacements, and in the optimal subreflector positions to focus a gravity-deformed main reflector. The results are of relevance to future design procedure.

  10. A Combined FEM/MoM/GTD Technique To Analyze Elliptically Polarized Cavity-Backed Antennas With Finite Ground Plane

    NASA Technical Reports Server (NTRS)

    Reddy, C. J.; Deshpande, M. D.; Fralick, D. T.; Cockrell, C. R.; Beck, F. B.

    1996-01-01

    Radiation pattern prediction analysis of elliptically polarized cavity-backed aperture antennas in a finite ground plane is performed using a combined Finite Element Method/Method of Moments/Geometrical Theory of Diffraction (FEM/MoM/GTD) technique. The magnetic current on the cavity-backed aperture in an infinite ground plane is calculated using the combined FEM/MoM analysis. GTD, including the slope diffraction contribution, is used to calculate the diffracted fields caused by both soft and hard polarizations at the edges of the finite ground plane. Explicit expressions for regular diffraction coefficients and slope diffraction coefficients are presented. The slope of the incident magnetic field at the diffraction points is derived and analytical expressions are presented. Numerical results for the radiation patterns of a cavity-backed circular spiral microstrip patch antenna excited by a coaxial probe in a finite rectangular ground plane are computed and compared with experimental results.

  11. Cyclic oxidation behavior of aluminide, platinum modified aluminide, and MCrAlY coatings on GTD-111

    SciTech Connect

    Cheruvu, N.S.; Chan, K.S.; Leverant, G.R.

    2000-01-01

    Cyclic oxidation behavior of aluminide, platinum modified aluminide, and MCrAlY coating has been investigated at three temperatures. Aluminide and platinum modified coating were deposited on GTD 111 material using an outward diffusion process. CoCrAlY coating was applied on GTD-111 by Electron Beam Physical Vapor Deposition (EB-PVD). The oxidation behavior of these coatings is characterized by weight change measurements and by the variation of {beta} phase present in the coating. The platinum modified aluminide coating exhibited the highest resistance to oxide scale spallation (weight loss) during cyclic oxidation testing. Metallographic techniques were used to determine the amount of {beta} phase and the aluminum content in a coating as a function of cycles. Cyclic oxidation life of these coatings is discussed in terms of the residual {beta} and aluminum content present in the coating after exposure. These results have been used to calibrate and validate a coating life model (COATLIFE) developed at the Material Center for Combustion Turbines (MCCT).

  12. Modelling of waves propagation on irregular surfaces using ray tracing and GTD approaches: Application to head waves simulation in TOFD inspections for NDT

    NASA Astrophysics Data System (ADS)

    Ferrand, Adrien; Darmon, Michel; Chatillon, Sylvain; Deschamps, Marc

    2014-04-01

    The Time of Flight Diffraction (TOFD) technique is a classical ultrasonic method used in ultrasonic non-destructive evaluation, which allows a precise positioning and a quantitative size evaluation of cracks in the inspected material. Among the typical phenomena arising in the current TOFD inspection, the so-called "head wave" is the first contribution reaching the receiver. The head wave propagation on a planar interface is well known and identified as a critical refraction taking place on the material surface. On irregular surfaces, it has been shown that the head wave results from the melting of surface and bulk waves mechanisms and that surface irregularities are responsible for numerous diffractions of the incident head wave. To simulate such behaviour, a model has been developed using a ray tracing technique based on time of flight minimization (generalized Fermat's principle). It enables the calculation of the ray path and the corresponding time of flight of all waves propagating in the material, including the head wave. To obtain a complete propagation model for these waves (both trajectory and amplitude), the integration of Geometrical Theory of Diffraction (GTD) models is currently performed by coupling them with the ray-based approach discussed above.

  13. Using GTD to Get Things Done at Your Library

    ERIC Educational Resources Information Center

    Hastings, Robin

    2011-01-01

    Librarians are the ultimate information workers, with little they can count as done at the end of the day. Staying productive and motivated when there are no finished items that you have created at day's end can be difficult. For just this reason, David Allen, author and productivity expert, has proposed an information-worker-centric theory of…

  14. Extending a GTD-based image formation technique to EUV lithography

    NASA Astrophysics Data System (ADS)

    Khoh, Andrew; Flagello, Donis G.; Milster, Thomas D.; Choi, Byoung-Il; Samudra, Ganesh S.; Wu, Yihong

    2003-06-01

    An image formation technique based on the Geometrical Theory of Diffraction was presented last conference. The technique is a scalar technique and is applicable to infinitely thin and perfectly conducting mask. We explore in this paper the extension of the technique to 1D Extreme Ultra-Violet(EUV) Lithography mask, taking into consideration both the material property and the topography of the mask. Vectorial nature of light is incorporated in the treatment. Results obtained are promising and encouraging. Computation time is relatively much shorter and the technique could simulate irradiance profile for any illumination angle. The technique is simple and elegant and lends understanding to image formation. We conclude that the asymmetry-through-focus characteristic usually found in EUV and Phase Mask imaging is an imaging phenomenon. We also conclude that corrections for proximity effect and pattern infidelity will be needed when EUV Lithography is introduced at the 32 nm node, assuming a system NA of 0.25. Lastly, for a partially coherent illumination, it appears necessary to compute the irradiance corresponding to each illumination point individually.

  15. Uniform GTD solution for the diffraction by metallic tapes on panelled compact-range reflectors

    NASA Technical Reports Server (NTRS)

    Somers, G. A.; Pathak, P. H.

    1992-01-01

    Metallic tape is commonly used to cover the interpanel gaps which occur in paneled compact-range reflectors. It is therefore of interest to study the effect of the scattering by the tape on the field in the target zone of the range. An analytical solution is presented for the target zone fields scattered by 2D metallic tapes. It is formulated by the generalized scattering matrix technique in conjunction with the Wiener-Hopf procedure. An extension to treat 3D tapes can be accomplished using the 2D solution via the equivalent current concept. The analytical solution is compared with a reference moment method solution to confirm the accuracy of the former.

  16. Diffraction by an arbitrary subreflector - GTD solution. [Geometrical Theory of Diffraction

    NASA Technical Reports Server (NTRS)

    Lee, S.-W.; Cramer, P., Jr.; Woo, K.; Rahmat-Samii, Y.

    1979-01-01

    The high-frequency asymptotic solution of diffraction by a conducting subreflector is investigated. The scattered field is determined up to and including terms of order k to the -1/2 relative to the incident field by using Keller's geometrical theory of diffraction and the newly developed uniform asymptotic theory of diffraction. The key feature of this approach is that the surface of the subreflector is completely arbitrary; in fact, it is only necessary to specify the surface at a set of discrete points over a random net.

  17. GTD analysis of airborne antennas radiating in the presence of lossy dielectric layers

    NASA Technical Reports Server (NTRS)

    Rojas-Teran, R. G.; Burnside, W. D.

    1981-01-01

    The patterns of monopole or aperture antennas mounted on a perfectly conducting convex surface radiating in the presence of a dielectric or metal plate are computed. The geometrical theory of diffraction is used to analyze the radiating system and extended here to include diffraction by flat dielectric slabs. Modified edge diffraction coefficients valid for wedges whose walls are lossy or lossless thin dielectric or perfectly conducting plates are developed. The width of the dielectric plates cannot exceed a quarter of a wavelength in free space, and the interior angle of the wedge is assumed to be close to 0 deg or 180 deg. Systematic methods for computing the individual components of the total high frequency field are discussed. The accuracy of the solutions is demonstrated by comparisons with measured results, where a 2 lambda by 4 lambda prolate spheroid is used as the convex surface. A jump or kink appears in the calculated pattern when higher order terms that are important are not included in the final solution. The most immediate application of the results presented here is in the modelling of structures such as aircraft which are composed of nonmetallic parts that play a significant role in the pattern.

  18. A uniform GTD analysis of the EM diffraction by a thin dielectric/ferrite half-plane and related configurations

    NASA Technical Reports Server (NTRS)

    Rojas, Roberto G.

    1985-01-01

    A uniform geometrical theory of diffraction (UTD) solution is developed for the problem of the diffraction by a thin dielectric/ferrite half plane when it is excited by a plane, cylindrical, or surface wave field. Both transverse electric and transverse magnetic cases are considered. The solution of this problem is synthesized from the solutions to the related problems of EM diffraction by configurations involving perfectly conducting electric and magnetic walls covered by a dielectric/ferrite half-plane of one half the thickness of the original half-plane.

  19. Identification of QTL associated with flower and runner production in octoploid strawberry (Fragaria × ananassa)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Seasonal flowering of strawberry is described as remontant and non-remontant. The genetic basis of this trait is important for breeding. This study was conducted to validate the existence of a major QTL for remontancy and weeks of flowering in F. × ananassa on LG IV, to determine if the level of flo...

  20. Computer modeling of electromagnetic problems using the geometrical theory of diffraction

    NASA Technical Reports Server (NTRS)

    Burnside, W. D.

    1976-01-01

    Some applications of the geometrical theory of diffraction (GTD), a high frequency ray optical solution to electromagnetic problems, are presented. GTD extends geometric optics, which does not take into account the diffractions occurring at edges, vertices, and various other discontinuities. Diffraction solutions, analysis of basic structures, construction of more complex structures, and coupling using GTD are discussed.

  1. Overview of the Solar Dynamic Ground Test Demonstration Program at the NASA Lewis Research Center

    NASA Technical Reports Server (NTRS)

    Shaltens, Richard K.

    1995-01-01

    The Solar Dynamic (SD) Ground Test Demonstration (GTD) program demonstrates the availability of SD technologies in a simulated space environment at the NASA Lewis Research Center (LERC) vacuum facility. Data from the SD GTD program will be provided to the joint U.S. and Russian team which is currently designing a 2 kW SD flight demonstration power system. This SD technology has the potential as a future power source for the International Space Station. This paper reviews the goals and status of the SD GTD program. A description of the SD GTD system includes key design features of the system, subsystems and components.

  2. Identification of the Isoform-specific Interactions between the Tail and the Head of Class V Myosin.

    PubMed

    Yao, Lin-Lin; Shen, Mei; Lu, Zekuan; Ikebe, Mitsuo; Li, Xiang-dong

    2016-04-01

    Vertebrates have three isoforms of class V myosin (Myo5), Myo5a, Myo5b, and Myo5c, which are involved in transport of multiple cargoes. It is well established that the motor functions of Myo5a and Myo5b are regulated by a tail inhibition mechanism. Here we found that the motor function of Myo5c was also inhibited by its globular tail domain (GTD), and this inhibition was abolished by high Ca(2+), indicating that the tail inhibition mechanism is conserved in vertebrate Myo5. Interestingly, we found that Myo5a-GTD and Myo5c-GTD were not interchangeable in terms of inhibition of motor function, indicating isoform-specific interactions between the GTD and the head of Myo5. To identify the isoform-specific interactions, we produced a number of Myo5 chimeras by swapping the corresponding regions of Myo5a and Myo5c. We found that Myo5a-GTD, with its H11-H12 loop being substituted with that of Myo5c, was able to inhibit the ATPase activity of Myo5c and that Myo5a-GTD was able to inhibit the ATPase activity of Myo5c-S1 and Myo5c-HMM only when their IQ1 motif was substituted with that of Myo5a. Those results indicate that the H11-H12 loop in the GTD and the IQ1 motif in the head dictate the isoform-specific interactions between the GTD and head of Myo5. Because the IQ1 motif is wrapped by calmodulin, whose conformation is influenced by the sequence of the IQ1 motif, we proposed that the calmodulin bound to the IQ1 motif interacts with the H11-H12 loop of the GTD in the inhibited state of Myo5. PMID:26912658

  3. DNA tests for strawberry: perpetual flowering - Bx215

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Perpetual flowering strawberries have great economic value to the fresh market industry. Floral initiation in strawberry is largely determined by photoperiod, temperature, and genetics. Commercially grown strawberries are generally classified as remontant (repeated or perpetual flowering, day neutr...

  4. Green tea decoction improves glucose tolerance and reduces weight gain of rats fed normal and high-fat diet.

    PubMed

    Snoussi, Chahira; Ducroc, Robert; Hamdaoui, Mohamed Hédi; Dhaouadi, Karima; Abaidi, Houda; Cluzeaud, Francoise; Nazaret, Corinne; Le Gall, Maude; Bado, André

    2014-05-01

    Green tea containing polyphenols exerts antidiabetic and antiobesity effects, but the mechanisms involved are not fully understood. In this study, we first analyzed and compared polyphenol compounds [epigallocatechin gallate (EGCG), epigallocatechin (EGC)] in decoction of green tea leaves versus usual green tea extracts. Second, the effects of acute (30 min) or chronic (6 weeks) oral administration of green tea decoction (GTD) on intestinal glucose absorption were studied in vitro in Ussing chamber, ex vivo using isolated jejunal loops and in vivo through glucose tolerance tests. Finally, we explore in rat model fed normal or high-fat diet the effects of GTD on body weight, blood parameters and on the relative expression of glucose transporters SGLT-1, GLUT2 and GLUT4. GTD cooked for 15 min contained the highest amounts of phenolic compounds. In fasted rats, acute administration of GTD inhibited SGLT-1 activity, increased GLUT2 activity and improved glucose tolerance. Similarly to GTD, acute administration of synthetic phenolic compounds (2/3 EGCG+1/3 EGC) inhibited SGLT-1 activity. Chronic administration of GTD in rat fed high-fat diet reduced body weight gain, circulating triglycerides and cholesterol and improved glucose tolerance. GTD-treated rats for 6 weeks display significantly reduced SGLT-1 and increased GLUT2 mRNA levels in the jejunum mucosa. Moreover, adipose tissue GLUT4 mRNA levels were increased. These results indicate that GTD, a traditional beverage rich in EGCG and EGC reduces intestinal SGLT-1/GLUT2 ratio, a hallmark of regulation of glucose absorption in enterocyte, and enhances adipose GLUT4 providing new insights in its possible role in the control of glucose homeostasis. PMID:24656388

  5. Green tea decoction improves glucose tolerance and reduces weight gain of rats fed normal and high-fat diet.

    PubMed

    Snoussi, Chahira; Ducroc, Robert; Hamdaoui, Mohamed Hédi; Dhaouadi, Karima; Abaidi, Houda; Cluzeaud, Francoise; Nazaret, Corinne; Le Gall, Maude; Bado, André

    2014-05-01

    Green tea containing polyphenols exerts antidiabetic and antiobesity effects, but the mechanisms involved are not fully understood. In this study, we first analyzed and compared polyphenol compounds [epigallocatechin gallate (EGCG), epigallocatechin (EGC)] in decoction of green tea leaves versus usual green tea extracts. Second, the effects of acute (30 min) or chronic (6 weeks) oral administration of green tea decoction (GTD) on intestinal glucose absorption were studied in vitro in Ussing chamber, ex vivo using isolated jejunal loops and in vivo through glucose tolerance tests. Finally, we explore in rat model fed normal or high-fat diet the effects of GTD on body weight, blood parameters and on the relative expression of glucose transporters SGLT-1, GLUT2 and GLUT4. GTD cooked for 15 min contained the highest amounts of phenolic compounds. In fasted rats, acute administration of GTD inhibited SGLT-1 activity, increased GLUT2 activity and improved glucose tolerance. Similarly to GTD, acute administration of synthetic phenolic compounds (2/3 EGCG+1/3 EGC) inhibited SGLT-1 activity. Chronic administration of GTD in rat fed high-fat diet reduced body weight gain, circulating triglycerides and cholesterol and improved glucose tolerance. GTD-treated rats for 6 weeks display significantly reduced SGLT-1 and increased GLUT2 mRNA levels in the jejunum mucosa. Moreover, adipose tissue GLUT4 mRNA levels were increased. These results indicate that GTD, a traditional beverage rich in EGCG and EGC reduces intestinal SGLT-1/GLUT2 ratio, a hallmark of regulation of glucose absorption in enterocyte, and enhances adipose GLUT4 providing new insights in its possible role in the control of glucose homeostasis.

  6. Geothermal energy program summary

    SciTech Connect

    Not Available

    1990-01-01

    The Geothermal Technology Division (GTD) of the US Department of Energy (DOE) is charged with the lead federal role in the research and development (R D) of technologies that will assist industry in economically exploiting the nation's vast geothermal resources. The GTD R D Program represents a comprehensive, balanced approach to establishing all forms of geothermal energy as significant contributors to the nation's energy supply. It is structured both to maintain momentum in the growth of the existing hydrothermal industry and to develop long-term options offering the greatest promise for practical applications. This volume, Volume 2, contains a detailed compilation of each GTD-funded R D activity performed by national laboratories or under contract to industrial, academic, and nonprofit research institutions.

  7. Bullae-Forming Pulmonary Metastasis from Choriocarcinoma Presenting as Pneumothorax

    PubMed Central

    Hyun, Kwanyong; Jeon, Hyeon Woo; Kim, Kyung Soo; Choi, Kook Bin; Park, Jae Kil; Park, Hyung Joo; Wang, Young Pil

    2015-01-01

    Gestational trophoblastic disease (GTD) is a condition of uncertain etiology, choriocarcioma, or placental-site hydatidiform moles, invasive moles, choriocarcinoma, and placental-site trophoblastic tumors. It arises from the abnormal proliferation of trophoblastic tissue and spreads beyond the uterus hematogenously. The early diagnosis of GTD is important to ensure timely and successful management and the preservation of fertility. We report the unusual case of a metastatic choriocarcinoma that formed bullae on the lung surface and presented as recurrent pneumothorax in a 38-year-old woman with elevated beta-human chorionic gonadotropin (hCG) levels. She underwent thoracoscopic wedge resection of the involved lung and four subsequent cycles of consolidation chemotherapy. No other evidence of metastatic disease or recurrent pneumothorax was noted during 22 months of follow-up. GTD should be considered in the differential diagnosis of spontaneous pneumothorax in reproductive-age women with an antecedent pregnancy and abnormal beta-hCG levels. PMID:26665116

  8. Update of the 2 Kw Solar Dynamic Ground Test Demonstration Program

    NASA Technical Reports Server (NTRS)

    Shaltens, Richard K.; Boyle, Robert V.

    1994-01-01

    The Solar Dynamic (SD) Ground Test Demonstration (GTD) program demonstrates the operation of a complete 2 kW, SD system in a simulated space environment at a NASA Lewis Research Center (LeRC) thermal-vacuum facility. This paper reviews the goals and status of the SD GTD program. A brief description of the SD system identifying key design features of the system, subsystems, and components is included. An aerospace industry/government team is working together to design, fabricate, assemble, and test a complete SD system.

  9. Overview of the solar dynamic ground test demonstration program

    NASA Technical Reports Server (NTRS)

    Shaltens, Richard K.; Boyle, Robert V.

    1993-01-01

    The Solar Dynamic (SD) Ground Test Demonstration (GTD) program demonstrates the availability of SD technologies in a simulated space environment at the NASA Lewis Research Center (LeRC) vacuum facility. An aerospace industry/ government team is working together to design, fabricate, build, and test a complete SD system. This paper reviews the goals and status of the SD GTD program. A description of the SD system includes key design features of the system, subsystems, and components as reported at the Critical Design Review (CDR).

  10. Bistatic scattering from a cone frustum

    NASA Technical Reports Server (NTRS)

    Ebihara, W.; Marhefka, R. J.

    1986-01-01

    The bistatic scattering from a perfectly conducting cone frustum is investigated using the Geometrical Theory of Diffraction (GTD). The first-order GTD edge-diffraction solution has been extended by correcting for its failure in the specular region off the curved surface and in the rim-caustic regions of the endcaps. The corrections are accomplished by the use of transition functions which are developed and introduced into the diffraction coefficients. Theoretical results are verified in the principal plane by comparison with the moment method solution and experimental measurements. The resulting solution for the scattered fields is accurate, easy to apply, and fast to compute.

  11. On the efficient calculation of the incomplete Airy function with application to edge diffraction

    NASA Astrophysics Data System (ADS)

    Cwik, Tom

    1988-12-01

    When the geometrical theory of diffraction (GTD) and its extensions are used to calculate fields across transition regions or in focal areas, various special functions are necessary to create uniform representations. One such transition function is the incomplete Airy function, which is applicable when two reflection points are arbitrarily close to each other and the endpoint of the domain considered. An efficient calculation of the incomplete Airy function is presented and shown to equal known asymptotic expansions when its argument is away from the critical point. By using these expansions, uniform field expressions are found which are consistent with the GTD and maintain its computational efficiency.

  12. Solution of electromagnetic scattering and radiation problems using a spectral domain approach - A review

    NASA Technical Reports Server (NTRS)

    Mittra, R.; Ko, W. L.; Rahmat-Samii, Y.

    1979-01-01

    This paper presents a brief review of some recent developments on the use of the spectral-domain approach for deriving high-frequency solutions to electromagnetics scattering and radiation problems. The spectral approach is not only useful for interpreting the well-known Keller formulas based on the geometrical theory of diffraction (GTD), it can also be employed for verifying the accuracy of GTD and other asymptotic solutions and systematically improving the results when such improvements are needed. The problem of plane wave diffraction by a finite screen or a strip is presented as an example of the application of the spectral-domain approach.

  13. Genetic mapping with octoploid strawberry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In 2004, the USDA-CSREES call for proposals for the National Research Initiative (NRI) Program 52.1, Plant Genetics, focused on crops within the plant family Rosaceae. Two of the funded projects focus on molecular marker mapping of flowering traits of strawberry: sex determination and remontancy. Bo...

  14. FBI-1 Is Overexpressed in Gestational Trophoblastic Disease and Promotes Tumor Growth and Cell Aggressiveness of Choriocarcinoma via PI3K/Akt Signaling.

    PubMed

    Mak, Victor C Y; Wong, Oscar G W; Siu, Michelle K Y; Wong, Esther S Y; Ng, Wai-Yan; Wong, Richard W C; Chan, Ka-Kui; Ngan, Hextan Y S; Cheung, Annie N Y

    2015-07-01

    Human placental trophoblasts can be considered pseudomalignant, with tightly controlled proliferation, apoptosis, and invasiveness. Gestational trophoblastic disease (GTD) represents a family of heterogeneous trophoblastic lesions with aberrant apoptotic and proliferative activities and dysregulation of cell signaling pathways. We characterize the oncogenic effects of factor that binds to the inducer of short transcripts of HIV-1 [FBI-1, alias POZ and Krüppel erythroid myeloid ontogenic factor (POKEMON)/ZBTB7A] in GTD and its role in promoting cell aggressiveness in vitro and tumor growth in vivo. IHC studies showed increased nuclear expression of FBI-1, including hydatidiform moles, choriocarcinoma (CCA), and placental site trophoblastic tumor, in GTD. In JAR and JEG-3 CCA cells, ectopic FBI-1 expression opposed apoptosis through repression of proapoptotic genes (eg, BAK1, FAS, and CASP8). FBI-1 overexpression also promoted Akt activation, as indicated by Akt-pS473 phosphorylation. FBI-1 overexpression promoted mobility and invasiveness of JEG-3 and JAR, but not in the presence of the phosphoinositide 3-kinase inhibitor LY294002. These findings suggest that FBI-1 could promote cell migration and invasion via phosphoinositide 3-kinase/Akt signaling. In vivo, nude mice injected with CCA cells with stable FBI-1 knockdown demonstrated reduced tumor growth compared with that in control groups. These findings suggest that FBI-1 is clinically associated with the progression of, and may be a therapeutic target in, GTD, owing to its diverse oncogenic effects on dysregulated trophoblasts. PMID:26093985

  15. FBI-1 Is Overexpressed in Gestational Trophoblastic Disease and Promotes Tumor Growth and Cell Aggressiveness of Choriocarcinoma via PI3K/Akt Signaling.

    PubMed

    Mak, Victor C Y; Wong, Oscar G W; Siu, Michelle K Y; Wong, Esther S Y; Ng, Wai-Yan; Wong, Richard W C; Chan, Ka-Kui; Ngan, Hextan Y S; Cheung, Annie N Y

    2015-07-01

    Human placental trophoblasts can be considered pseudomalignant, with tightly controlled proliferation, apoptosis, and invasiveness. Gestational trophoblastic disease (GTD) represents a family of heterogeneous trophoblastic lesions with aberrant apoptotic and proliferative activities and dysregulation of cell signaling pathways. We characterize the oncogenic effects of factor that binds to the inducer of short transcripts of HIV-1 [FBI-1, alias POZ and Krüppel erythroid myeloid ontogenic factor (POKEMON)/ZBTB7A] in GTD and its role in promoting cell aggressiveness in vitro and tumor growth in vivo. IHC studies showed increased nuclear expression of FBI-1, including hydatidiform moles, choriocarcinoma (CCA), and placental site trophoblastic tumor, in GTD. In JAR and JEG-3 CCA cells, ectopic FBI-1 expression opposed apoptosis through repression of proapoptotic genes (eg, BAK1, FAS, and CASP8). FBI-1 overexpression also promoted Akt activation, as indicated by Akt-pS473 phosphorylation. FBI-1 overexpression promoted mobility and invasiveness of JEG-3 and JAR, but not in the presence of the phosphoinositide 3-kinase inhibitor LY294002. These findings suggest that FBI-1 could promote cell migration and invasion via phosphoinositide 3-kinase/Akt signaling. In vivo, nude mice injected with CCA cells with stable FBI-1 knockdown demonstrated reduced tumor growth compared with that in control groups. These findings suggest that FBI-1 is clinically associated with the progression of, and may be a therapeutic target in, GTD, owing to its diverse oncogenic effects on dysregulated trophoblasts.

  16. A Demands-Resources Model of Work Pressure in IT Student Task Groups

    ERIC Educational Resources Information Center

    Wilson, E. Vance; Sheetz, Steven D.

    2010-01-01

    This paper presents an initial test of the group task demands-resources (GTD-R) model of group task performance among IT students. We theorize that demands and resources in group work influence formation of perceived group work pressure (GWP) and that heightened levels of GWP inhibit group task performance. A prior study identified 11 factors…

  17. Results from a randomized trial of a web-based, tailored decision aid for women at high risk for breast cancer

    PubMed Central

    Banegas, Matthew P.; McClure, Jennifer B.; Barlow, William E.; Ubel, Peter A.; Smith, Dylan M.; Zikmund-Fisher, Brian J.; Greene, Sarah M.; Fagerlin, Angela

    2013-01-01

    Objective To assess the impact of Guide to Decide (GtD), a web-based, personally-tailored decision aid designed to inform women’s decisions about prophylactic tamoxifen and raloxifene use. Methods Postmenopausal women, age 46–74, with BCRAT 5-year risk ≥1.66% and no prior history of breast cancer were randomized to one of three study arms: intervention (n = 690), Time 1 control (n = 160), or 3-month control (n = 162). Intervention participants viewed GtD prior to completing a post-test and 3 month follow-up assessment. Controls did not. We assessed the impact of GtD on women’s decisional conflict levels and treatment decision behavior at post-test and at 3 months, respectively. Results Intervention participants had significantly lower decisional conflict levels at post-test (p < 0.001) and significantly higher odds of making a decision about whether or not to take prophylactic tamoxifen or raloxifene at 3-month follow-up (p < 0.001) compared to control participants. Conclusion GtD lowered decisional conflict and helped women at high risk of breast cancer decide whether to take prophylactic tamoxifen or raloxifene to reduce their cancer risk. Practice implications Web-based, tailored decision aids should be used more routinely to facilitate informed medical decisions, reduce patients’ decisional conflict, and empower patients to choose the treatment strategy that best reflects their own values. PMID:23395006

  18. Masking autoprocessing of Clostridium difficile toxin A by the C-terminus combined repetitive oligo peptides.

    PubMed

    Zhang, Yongrong; Hamza, Therwa; Gao, Si; Feng, Hanping

    2015-04-01

    Clostridium difficile toxin A and B (TcdA and TcdB) are the major virulence factors of the bacterium, both of which consist of two enzymatic domains: an effector glucosyltransferase domain (GTD) and a cysteine protease domain (CPD) responsible for autocleavage and release of GTD. Although the CPDs from both toxins share a similar structure and mechanism of hexakisphosphate (InsP6)-induced activation, TcdA is substantially less sensitive to the autocleavage as compared with TcdB. In this study, we provided evidence of inter-domain regulation of CPD activity of TcdA and its autoprocessing. The C-terminus combined repetitive oligo peptides (CROPs) of TcdA reduced the accessibility of TcdB CPD to its substrate in a chimeric toxin TxB-Ar, consequently blocking autoprocessing. Moreover, interference of antibodies with the CROPs of full-length TcdA efficiently enhanced its GTD release. In conclusion, by utilizing chimeric toxins and specific antibodies, we identified that the CROPs of TcdA plays a crucial role in controlling the InsP6-mediated activation of CPD and autocleavage of GTD. Our data provides insights on the molecular mode of action of the C. difficile toxins.

  19. Selection of Solar Simulator for Solar Dynamic Ground Test

    NASA Technical Reports Server (NTRS)

    Tolbert, Carol M.

    1994-01-01

    The 2 kWe Solar Dynamic (SD) Ground Test Demonstration (GTD) experiment will be conducted in 1995 at NASA Lewis Research Center (LeRC). This solar dynamic power system test will be conducted in a simulated space environment and will require an artificial sun. To address the solar simulator requirements for the GTD, Arnold Engineering Development Center (AEDC) was hired under contract to review and visit four existing solar simulator facilities. The four facilities included, AEDC's Mark 1 Chamber, NASA-JSC Chamber A, AEDC's 12V Chamber, and NASA-JPL Space Simulator Chamber. Two design concepts were considered following several months of evaluating existing solar simulator facilities throughout the United States. To satisfy system requirements for the SD GTD experiment the solar simulator needs to provide a uniform light flux to the SD concentrator, provide the light within a subtense angle of one degree, and provide an intensity of one solar constant (1.37 kW/sq m) at airmass zero. Most solar simulators are designed for supplying heat loads to spacecraft where a cone angle as large as 3 degrees is acceptable. It was also concluded that a solar simulator, such like these considered in the AEDC study, would require major facility modifications for NASA LeRC and result in significant impacts to the program. The advanced solar simulator concept developed by NASA LeRC will meet the system requirements for the SD GTD experiment Since SD GTD solar simulator requirements could not be addressed by existing simulator, an advanced concept was considered.

  20. High-frequency techniques for RCS prediction of plate geometries

    NASA Technical Reports Server (NTRS)

    Balanis, Constantine A.; Polka, Lesley A.

    1992-01-01

    The principal-plane scattering from perfectly conducting and coated strips and rectangular plates is examined. Previous reports have detailed Geometrical Theory of Diffraction/Uniform Theory of Diffraction (GTD/UTD) solutions for these geometries. The GTD/UTD solution for the perfectly conducting plate yields monostatic radar cross section (RCS) results that are nearly identical to measurements and results obtained using the Moment Method (MM) and the Extended Physical Theory of Diffraction (EPTD). This was demonstrated in previous reports. The previous analysis is extended to bistatic cases. GTD/UTD results for the principal-plane scattering from a perfectly conducting, infinite strip are compared to MM and EPTD data. A comprehensive overview of the advantages and disadvantages of the GTD/UTD and of the EPTD and a detailed analysis of the results from both methods are provided. Several previous reports also presented preliminary discussions and results for a GTD/UTD model of the RCS of a coated, rectangular plate. Several approximations for accounting for the finite coating thickness, plane-wave incidence, and far-field observation were discussed. Here, these approximations are replaced by a revised wedge diffraction coefficient that implicitly accounts for a coating on a perfect conductor, plane-wave incidence, and far-field observation. This coefficient is computationally more efficient than the previous diffraction coefficient because the number of Maliuzhinets functions that must be calculated using numerical integration is reduced by a factor of 2. The derivation and the revised coefficient are presented in detail for the hard polarization case. Computations and experimental data are also included. The soft polarization case is currently under investigation.

  1. Selection of solar simulator for solar dynamic ground test

    NASA Astrophysics Data System (ADS)

    Tolbert, Carol M.

    1994-08-01

    The 2 kWe Solar Dynamic (SD) Ground Test Demonstration (GTD) experiment will be conducted in 1995 at NASA Lewis Research Center (LeRC). This solar dynamic power system test will be conducted in a simulated space environment and will require an artificial sun. To address the solar simulator requirements for the GTD, Arnold Engineering Development Center (AEDC) was hired under contract to review and visit four existing solar simulator facilities. The four facilities included, AEDC's Mark 1 Chamber, NASA-JSC Chamber A, AEDC's 12V Chamber, and NASA-JPL Space Simulator Chamber. Two design concepts were considered following several months of evaluating existing solar simulator facilities throughout the United States. To satisfy system requirements for the SD GTD experiment the solar simulator needs to provide a uniform light flux to the SD concentrator, provide the light within a subtense angle of one degree, and provide an intensity of one solar constant (1.37 kW/sq m) at airmass zero. Most solar simulators are designed for supplying heat loads to spacecraft where a cone angle as large as 3 degrees is acceptable. It was also concluded that a solar simulator, such like these considered in the AEDC study, would require major facility modifications for NASA LeRC and result in significant impacts to the program. The advanced solar simulator concept developed by NASA LeRC will meet the system requirements for the SD GTD experiment Since SD GTD solar simulator requirements could not be addressed by existing simulator, an advanced concept was considered.

  2. A Novel Teflon-membrane Gas Tension Device for Denitrification-studies in Oxygen Minimum Zones

    NASA Astrophysics Data System (ADS)

    Reed, A. C.; McNeil, C. L.; D'Asaro, E. A.; Altabet, M. A.; Johnson, B.; Bourbonnais, A.

    2014-12-01

    Oxygen Minimum Zones (OMZs) are global hotspots for the biogeochemical transformation of biologically-available forms of nitrogen to unusable nitrogen-gas. We present a new Teflon-membrane based Gas Tension Device (GTD) for measuring the excess N2 signal generated by denitrification and anammox in OMZs, with a hydrostatic pressure-independent response and a depth range from 0 - 550 m, a significant advancement from previous GTD models. The GTD consists of a 4/1000" thick by 2" diameter Teflon-membrane with a water-side plenum connected to SeaBird 5T pump. Dissolved gases in the water equilibrate across the membrane with a low-dead-volume housing connected to a high-precision quart pressure sensor. Laboratory data characterizing the GTD will be presented. The e-folding (response) time ranges from 14 min at continuous (100%) pumping to 28 min at pulse (10%) pumping. We also demonstrate the pressure dependence of the partial pressures from Henry's Law in the laboratory for pure nitrogen, pure oxygen, and standard atmospheric ratios of gases. GTD's were field tested on two floats deployed in the Eastern Tropical North Pacific (ETNP) OMZ for 15 days that targeted a productive mesoscale surface eddy originating from the Mexican coast. We anticipated that high organic carbon export should stimulate denitrification within the OMZ below. The floats profiled between the surface and 400 m depth and concurrently measured T, S, PAR, O2 (SBE 43 and Optode), and nitrate (SUNA). The N2-profiles from the GTDs are validated against independently measured N2/Ar ratio data collected during the deployment.

  3. An Investigative Study into Psychological and Fertility Sequelae of Gestational Trophoblastic Disease: The Impact on Patients’ Perceived Fertility, Anxiety and Depression

    PubMed Central

    Di Mattei, Valentina E.; Carnelli, Letizia; Bernardi, Martina; Pagani Bagliacca, Elena; Zucchi, Paola; Lavezzari, Luca; Giorgione, Veronica; Ambrosi, Alessandro; Mangili, Giorgia; Candiani, Massimo; Sarno, Lucio

    2015-01-01

    Objectives Gestational Trophoblastic Disease (GTD) comprises a group of disorders that derive from the placenta. Even if full recovery is generally expected, women diagnosed with GTD have to confront: the loss of a pregnancy, a potentially life-threatening diagnosis and delays in future pregnancies. The aim of the study is to evaluate the psychological impact of GTD, focusing on perceived fertility, depression and anxiety. Methods 37 patients treated for GTD at San Raffaele Hospital, Milan, took part in the study. The STAI-Y (State-Trait Anxiety Inventory), the BDI-SF (Beck Depression Scale-Short Form) and the FPI (Fertility Problem Inventory) were used. Patients were grouped on the basis of presence of children (with or without), age (< or ≥35) and type of diagnosis (Hydatidiform Mole, HM, or Gestational Trophoblastic Neoplasia, GTN). Differences in the values between variables were assessed by a t-type test statistic. Three-way ANOVAs were also carried out considering the same block factors. Results The study highlights that women suffering from GTN had higher depression scores compared to women suffering from HM. A significant correlation was found between anxiety (state and trait) and depression. Younger women presented higher Global Stress scores on the FPI, especially tied to Need for Parenthood and Relationship Concern subscales. Need for Parenthood mean scores significantly varied between women with and without children too. Conclusions We can conclude that fertility perception seems to be negatively affected by GTD diagnosis, particularly in younger women and in those without children. Patients should be followed by a multidisciplinary team so as to be supported in the disease’s psychological aspects too. PMID:26030770

  4. Grapevine trunk diseases associated with fungi from the Diaporthaceae family in Croatian vineyards.

    PubMed

    Kaliterna, Joško; Miličević, Tihomir; Cvjetković, Bogdan

    2012-12-01

    Grapevine trunk diseases (GTD) have a variety of symptoms and causes. The latter include fungal species from the family Diaporthaceae. The aim of our study was to determine Diaporthaceae species present in the woody parts of grapevines sampled from 12 vine-growing coastal and continental areas of Croatia. The fungi were isolated from diseased wood, and cultures analysed for phenotype (morphology and pathogenicity) and DNA sequence (ITS1, 5.8S, ITS2). Most isolates were identified as Phomopsis viticola, followed by Diaporthe neotheicola and Diaporthe eres. This is the first report of Diaporthe eres as a pathogen on grapevine in the world, while for Diaporthe neotheicola this is the first report in Croatia. Pathogenicity trials confirmed Phomopsis viticola as a strong and Diaporthe neotheicola as a weak pathogen. Diaporthe eres turned out to be a moderate pathogen, which implies that the species could have a more important role in the aetiology of GTD.

  5. Thermodynamics and Geometry of Strange Quark Matter

    NASA Astrophysics Data System (ADS)

    Gholizade, H.; Altaibayeva, A.; Myrzakulov, R.

    2015-06-01

    We study thermodynamic of strange quark matter (SQM) using the analytic expressions of free and internal energies. We investigate two regimes of the high density and low density separately. As a vital program, in the case of a massless gluon and massless quarks at finite temperature, we also present a geometry of thermodynamics for the gluon and Bosons using a Legendre invariance metric ,it is so called as geometrothermodynamic (GTD) to better understanding of the phase transition. The GTD metric and its second order scalar invariant have been obtained and we clarify the phase transition by study the singularities of the scalar curvature of this Riemannian metric. This method is ensemble dependence and to complete the phase transition, meanwhile we also investigate enthalpy and entropy and internal energy representations. Our work exposes new pictures of the nature of phase transitions in SQM.

  6. Wireless Video System for Extra Vehicular Activity in the International Space Station and Space Shuttle Orbiter Environment

    NASA Technical Reports Server (NTRS)

    Loh, Yin C.; Boster, John; Hwu, Shian; Watson, John C.; deSilva, Kanishka; Piatek, Irene (Technical Monitor)

    1999-01-01

    The Wireless Video System (WVS) provides real-time video coverage of astronaut extra vehicular activities during International Space Station (ISS) assembly. The ISS wireless environment is unique due to the nature of the ISS structure and multiple RF interference sources. This paper describes how the system was developed to combat multipath, blockage, and interference using an automatic antenna switching system. Critical to system performance is the selection of receiver antenna installation locations determined using Uniform Geometrical Theory of Diffraction (GTD) techniques.

  7. The relationship of microstructure to fracture and corrosion behavior of a directionally solidified superalloy

    NASA Astrophysics Data System (ADS)

    Trexler, Matthew D.

    GTD-111 DS is a directionally solidified superalloy currently used in turbine engines. To accurately predict the life of engine components it is essential to examine and characterize the microstructural evolution of the material and its effects on material properties. The as-cast microstructure of GTD-111 is highly inhomogeneous as a result of coring. The current post-casting heat treatments do not effectively eliminate the inhomogeneity. This inhomogeneity affects properties including tensile strength, fracture toughness, fracture path, and corrosion behavior, primarily in terms of the number of grains per specimen. The goal of this work was to link microstructural features to these properties. Quantitative fractography was used to determine that the path of cracks during failure of tensile specimens is influenced by the presence of carbides, which are located in the interdendritic regions of the material as dictated by segregation. The solvus temperature of the precipitate phase, Ni3(Al, Ti), was determined to be 1200°C using traditional metallography, differential thermal analysis, and dilatometry. A heat-treatment was designed to homogenize the microstructure for tensile testing that isolates the carbide by dissolving all of the "eutectic" Ni3(Al, Ti) precipitate phase, which is also found in the interdendritic areas. High temperature oxidation/sulfidation tests were conducted to investigate the corrosion processes involved when GTD-111 DS is utilized in steam and gas combustion turbine engines. The kinetics of corrosion in both oxidizing and sulfidizing atmospheres were determined using thermogravimetric analysis. Additionally, metallography of these samples after TGA revealed a correlation between the presence of grain boundaries and sulfur attack, which led to catastrophic failure of the material under stress-free conditions in a sulfur bearing environment. In summary, this work correlates the inhomogeneous microstructure of GTD-111 DS to tensile fracture

  8. Microstrip antenna modeling and measurement at high frequencies

    SciTech Connect

    Bevensee, R.M.

    1986-04-30

    This report addresses the task C(i) of the Proposal for Microstrip Antenna Modeling and Measurement at High Frequencies by the writer, July 1985. The task is: Assess the advantages and disadvantages of the three computational approaches outlined in the Proposal, including any difficulties to be resolved and an estimate of the time required to implement each approach. The three approaches are (1) Finite Difference, (2) Sommerfeld-GTD-MOM, and (3) Surface Intergral Equations - MOM. These are discussed in turn.

  9. Evaluation of Two Computational Techniques of Calculating Multipath Using Global Positioning System Carrier Phase Measurements

    NASA Technical Reports Server (NTRS)

    Gomez, Susan F.; Hood, Laura; Panneton, Robert J.; Saunders, Penny E.; Adkins, Antha; Hwu, Shian U.; Lu, Ba P.

    1996-01-01

    Two computational techniques are used to calculate differential phase errors on Global Positioning System (GPS) carrier war phase measurements due to certain multipath-producing objects. The two computational techniques are a rigorous computati electromagnetics technique called Geometric Theory of Diffraction (GTD) and the other is a simple ray tracing method. The GTD technique has been used successfully to predict microwave propagation characteristics by taking into account the dominant multipath components due to reflections and diffractions from scattering structures. The ray tracing technique only solves for reflected signals. The results from the two techniques are compared to GPS differential carrier phase ns taken on the ground using a GPS receiver in the presence of typical International Space Station (ISS) interference structures. The calculations produced using the GTD code compared to the measured results better than the ray tracing technique. The agreement was good, demonstrating that the phase errors due to multipath can be modeled and characterized using the GTD technique and characterized to a lesser fidelity using the DECAT technique. However, some discrepancies were observed. Most of the discrepancies occurred at lower devations and were either due to phase center deviations of the antenna, the background multipath environment, or the receiver itself. Selected measured and predicted differential carrier phase error results are presented and compared. Results indicate that reflections and diffractions caused by the multipath producers, located near the GPS antennas, can produce phase shifts of greater than 10 mm, and as high as 95 mm. It should be noted tl the field test configuration was meant to simulate typical ISS structures, but the two environments are not identical. The GZ and DECAT techniques have been used to calculate phase errors due to multipath o the ISS configuration to quantify the expected attitude determination errors.

  10. The finite ground plane effect on the microstrip antenna radiation patterns

    NASA Technical Reports Server (NTRS)

    Huang, J.

    1983-01-01

    The uniform geometrical theory of diffraction (GTD) is employed for calculating the edge diffracted fields from the finite ground plane of a microstrip antenna. The source field from the radiating patch is calculated by two different methods: the slot theory and the modal expansion theory. Many numerical and measured results are presented to demonstrate the accuracy of the calculations and the finite ground plane edge effect.

  11. A study of three techniques used in the diffraction analysis of shaped dual-reflector antennas

    NASA Technical Reports Server (NTRS)

    Cwik, Tom A.; Kildal, Per-Simon

    1989-01-01

    An examination is presented of three techniques used for the efficient computation of fields diffracted by a subreflector that has been shaped by geometrical optics synthesis. It is found that these techniques, which are based on the geometrical theory of diffraction (GTD), produce errors in the computed fields that are specific to shaped reflectors. These errors are examined for a reflector system shaped to produce maximum gain from a tapered feed illumination. The discrepancies are directly related to the caustic being located near an observation point of the GTD calculations. The errors found are localized, and they increase in magnitude as the caustic approaches the main reflector. In a general offset geometry, the location of the caustic may be located arbitrarily close to the main reflector given a prescribed output aperture distribution. For the specific case considered here-the common situation of shaping to produce maximum gain-the caustic is located near the edge of the main reflector and on the reflection shadow boundary. A local correction is derived which creates a uniform solution through the caustic and across the reflection shadow boundary. Away from this point the calculation receeds to the standard GTD solution.

  12. Rigorous diffraction analysis using geometrical theory of diffraction for future mask technology

    NASA Astrophysics Data System (ADS)

    Chua, Gek S.; Tay, Cho J.; Quan, Chenggen; Lin, Qunying

    2004-05-01

    Advanced lithographic techniques such as phase shift masks (PSM) and optical proximity correction (OPC) result in a more complex mask design and technology. In contrast to the binary masks, which have only transparent and nontransparent regions, phase shift masks also take into consideration transparent features with a different optical thickness and a modified phase of the transmitted light. PSM are well-known to show prominent diffraction effects, which cannot be described by the assumption of an infinitely thin mask (Kirchhoff approach) that is used in many commercial photolithography simulators. A correct prediction of sidelobe printability, process windows and linearity of OPC masks require the application of rigorous diffraction theory. The problem of aerial image intensity imbalance through focus with alternating Phase Shift Masks (altPSMs) is performed and compared between a time-domain finite-difference (TDFD) algorithm (TEMPEST) and Geometrical theory of diffraction (GTD). Using GTD, with the solution to the canonical problems, we obtained a relationship between the edge on the mask and the disturbance in image space. The main interest is to develop useful formulations that can be readily applied to solve rigorous diffraction for future mask technology. Analysis of rigorous diffraction effects for altPSMs using GTD approach will be discussed.

  13. Characterization of two novel plasmids from Geobacillus sp. 610 and 1121 strains.

    PubMed

    Kananavičiūtė, Rūta; Butaitė, Elena; Citavičius, Donaldas

    2014-01-01

    We describe two cryptic low molecular weight plasmids, pGTD7 (3279bp) and pGTG5 (1540bp), isolated from Geobacillus sp. 610 and 1121 strains, respectively. Homology analysis of the replication protein (Rep) sequences and detection of ssDNA indicate that both of them replicate via rolling circle mechanism. As revealed by sequence similarities of dso region and Rep protein, plasmid pGTD7 belongs to pC194/pUB110 plasmid family. The replicon of pGTD7 was proved to be functional in another Geobacillus host. For this purpose, a construct pUCK7, containing a replicon of the analyzed plasmid, was created and transferred to G. stearothermophilus NUB3621R strain by electroporation. Plasmid pGTG5, based on Rep protein sequence similarity, was found to be related mostly to some poorly characterized bacterial plasmids. Rep proteins encoded by these plasmids contain conservative motifs that are most similar to those of Microviridae phages. This feature suggests that pGTG5, together with other plasmids containing the same motifs, could constitute a new family of bacterial plasmids. To date, pGTG5 is the smallest plasmid identified in bacteria belonging to the genus Geobacillus. The two plasmids described in this study can be used for the construction of new vectors suitable for biotechnologically important bacteria of the genus Geobacillus.

  14. Geothermal energy program summary: Volume 2, Research summaries, fiscal year 1988

    SciTech Connect

    Not Available

    1989-03-01

    The Geothermal Technology Division (GTD) of the US Department of Energy (DOE) is charged with the lead federal role in the research and development (R&D) of technologies that will assist industry in economically exploiting the nation`s vast geothermal resources. The GTD R&D program represents a comprehensive, balanced approach to establishing all forms of geothermal energy as significant contributors to the nation`s energy supply. It is structured both to maintain momentum in the growth of the existing hydrothermal industry and to develop long-term options offering the greatest promise for practical applications. The Geothermal Energy Program Summary for Fiscal Year 1988 is a two-volume set designed to be an easily accessible reference to inform the US geothermal industry and other interested parties of the technological advances and progress achieved in the DOE geothermal program as well as to describe the thrust of the current R&D effort and future R&D directions. This volume, Volume II, contains a detailed compilation of each GTD-funded R&D activity performed by national laboratories or under contract to industrial, academic, and nonprofit research institutions. The Program Summary is intended as an important technology transfer vehicle to assure the wide and timely dissemination of information concerning the department`s geothermal research.

  15. Integrated Historical Tsunami Event and Deposit Database

    NASA Astrophysics Data System (ADS)

    Dunbar, P. K.; McCullough, H. L.

    2010-12-01

    The National Geophysical Data Center (NGDC) provides integrated access to historical tsunami event, deposit, and proxy data. The NGDC tsunami archive initially listed tsunami sources and locations with observed tsunami effects. Tsunami frequency and intensity are important for understanding tsunami hazards. Unfortunately, tsunami recurrence intervals often exceed the historic record. As a result, NGDC expanded the archive to include the Global Tsunami Deposits Database (GTD_DB). Tsunami deposits are the physical evidence left behind when a tsunami impacts a shoreline or affects submarine sediments. Proxies include co-seismic subsidence, turbidite deposits, changes in biota following an influx of marine water in a freshwater environment, etc. By adding past tsunami data inferred from the geologic record, the GTD_DB extends the record of tsunamis backward in time. Although the best methods for identifying tsunami deposits and proxies in the geologic record remain under discussion, developing an overall picture of where tsunamis have affected coasts, calculating recurrence intervals, and approximating runup height and inundation distance provides a better estimate of a region’s true tsunami hazard. Tsunami deposit and proxy descriptions in the GTD_DB were compiled from published data found in journal articles, conference proceedings, theses, books, conference abstracts, posters, web sites, etc. The database now includes over 1,200 descriptions compiled from over 1,100 citations. Each record in the GTD_DB is linked to its bibliographic citation where more information on the deposit can be found. The GTD_DB includes data for over 50 variables such as: event description (e.g., 2010 Chile Tsunami), geologic time period, year, deposit location name, latitude, longitude, country, associated body of water, setting during the event (e.g., beach, lake, river, deep sea), upper and lower contacts, underlying and overlying material, etc. If known, the tsunami source mechanism

  16. Bacteria in a wood fungal disease: characterization of bacterial communities in wood tissues of esca-foliar symptomatic and asymptomatic grapevines

    PubMed Central

    Bruez, Emilie; Haidar, Rana; Alou, Maryam T.; Vallance, Jessica; Bertsch, Christophe; Mazet, Flore; Fermaud, Marc; Deschamps, Alain; Guerin-Dubrana, Lucia; Compant, Stéphane; Rey, Patrice

    2015-01-01

    Esca is a grapevine trunk disease (GTD) associated with different pathogenic fungi inhabiting the woody tissues. Bacteria can also be found in such tissues and they may interact with these fungal colonizers. Although such types of microbial interactions have been observed for wood diseases in many trees, this has never been studied for grapevine. In this study, the bacterial microflora of different vine status (esca-symptomatic and asymptomatic), different anatomical part (trunk and cordon) and different type of tissues (necrotic or not) have been studied. Based on Single Strand Conformation Polymorphism (SSCP) analyses, data showed that (i) specific complexes of bacterial microflora colonize the wood of both necrotic and non-necrotic tissues of esca-foliar symptomatic and asymptomatic vines, and also that (ii) depending on the anatomical part of the plant, cordon or trunk, differences could be observed between the bacterial communities. Such differences were also revealed through the community-level physiological profiling (CLPP) with Biolog EcoplatesTM. Two hundred seventeen bacterial strains were also isolated from plant samples and then assigned to bacterial species based on the 16S rRNA genes. Although Bacillus sp. and Pantoea agglomerans were the two most commonly isolated species from all kinds of tissues, various other taxa were also isolated. Inoculation of vine cuttings with 14 different bacterial species, and one GTD fungus, Neofusicoccum parvum, showed no impact of these bacteria on the size of the wood necroses caused by N. parvum. This study showed, therefore, that bacterial communities differ according to the anatomical part (trunk or cordon) and/or the type of tissue (necrotic or non-necrotic) of wood of grapevine plants showing external symptoms of esca disease. However, research into bacteria having a role in GTD development needs further studies. PMID:26579076

  17. Bacteria in a wood fungal disease: characterization of bacterial communities in wood tissues of esca-foliar symptomatic and asymptomatic grapevines.

    PubMed

    Bruez, Emilie; Haidar, Rana; Alou, Maryam T; Vallance, Jessica; Bertsch, Christophe; Mazet, Flore; Fermaud, Marc; Deschamps, Alain; Guerin-Dubrana, Lucia; Compant, Stéphane; Rey, Patrice

    2015-01-01

    Esca is a grapevine trunk disease (GTD) associated with different pathogenic fungi inhabiting the woody tissues. Bacteria can also be found in such tissues and they may interact with these fungal colonizers. Although such types of microbial interactions have been observed for wood diseases in many trees, this has never been studied for grapevine. In this study, the bacterial microflora of different vine status (esca-symptomatic and asymptomatic), different anatomical part (trunk and cordon) and different type of tissues (necrotic or not) have been studied. Based on Single Strand Conformation Polymorphism (SSCP) analyses, data showed that (i) specific complexes of bacterial microflora colonize the wood of both necrotic and non-necrotic tissues of esca-foliar symptomatic and asymptomatic vines, and also that (ii) depending on the anatomical part of the plant, cordon or trunk, differences could be observed between the bacterial communities. Such differences were also revealed through the community-level physiological profiling (CLPP) with Biolog Ecoplates(TM). Two hundred seventeen bacterial strains were also isolated from plant samples and then assigned to bacterial species based on the 16S rRNA genes. Although Bacillus sp. and Pantoea agglomerans were the two most commonly isolated species from all kinds of tissues, various other taxa were also isolated. Inoculation of vine cuttings with 14 different bacterial species, and one GTD fungus, Neofusicoccum parvum, showed no impact of these bacteria on the size of the wood necroses caused by N. parvum. This study showed, therefore, that bacterial communities differ according to the anatomical part (trunk or cordon) and/or the type of tissue (necrotic or non-necrotic) of wood of grapevine plants showing external symptoms of esca disease. However, research into bacteria having a role in GTD development needs further studies. PMID:26579076

  18. Performance and durability of high emittance heat receiver surfaces for solar dynamic power systems

    NASA Technical Reports Server (NTRS)

    Degroh, Kim K.; Roig, David M.; Burke, Christopher A.; Shah, Dilipkumar R.

    1994-01-01

    Haynes 188, a cobalt-based superalloy, will be used to make thermal energy storage (TES) containment canisters for a 2 kW solar dynamic ground test demonstrator (SD GTD). Haynes 188 containment canisters with a high thermal emittance (epsilon) are desired for radiating heat away from local hot spots, improving the heating distribution, which will in turn improve canister service life. In addition to needing a high emittance, the surface needs to be durable in an elevated temperature, high vacuum environment for an extended time period. Thirty-five Haynes 188 samples were exposed to 14 different types of surface modification techniques for emittance and vacuum heat treatment (VHT) durability enhancement evaluation. Optical properties were obtained for the modified surfaces. Emittance enhanced samples were exposed to VHT for up to 2692 hours at 827 C and less than or equal to 10(exp -6) torr with integral thermal cycling. Optical properties were taken intermittently during exposure, and after final VHT exposure. The various surface modification treatments increased the emittance of pristine Haynes 188 from 0.11 up to 0.86. Seven different surface modification techniques were found to provide surfaces which met the SD GTD receiver VHT durability requirement. Of the 7 surface treatments, 2 were found to display excellent VHT durability: an alumina based (AB) coating and a zirconia based coating. The alumina based coating was chosen for the epsilon enhancement surface modification technique for the SD GTD receiver. Details of the performance and vacuum heat treatment durability of this coating and other Haynes 188 emittance surface modification techniques are discussed. Technology from this program will lead to successful demonstration of solar dynamic power for space applications, and has potential for application in other systems requiring high emittance surfaces.

  19. Clostridium sordellii Lethal-Toxin Autoprocessing and Membrane Localization Activities Drive GTPase Glucosylation Profiles in Endothelial Cells

    PubMed Central

    Craven, Ryan

    2015-01-01

    ABSTRACT Clostridium sordellii infections cause gangrene and edema in humans and gastrointestinal infections in livestock. One of the principle virulence factors is TcsL, a large protein toxin which glucosylates host GTPases to cause cytopathic and cytotoxic effects. TcsL has two enzymatic domains, an N-terminal glucosyltransferase domain (GTD) and an autoprocessing domain responsible for release of the GTD within the cell. The GTD can then use its N-terminal membrane localization domain (MLD) for orientation on membranes and modification of GTPases. This study describes the use of conditionally immortalized murine pulmonary microvascular endothelial cells as a model for the study of TcsL functional activities. Point mutations that disrupt the glucosyltransferase, autoprocessing, or membrane localization activities were introduced into a recombinant version of TcsL, and the activities of these mutants were compared to those of wild-type toxin. We observed that all mutants are defective or impaired in cytotoxicity but differ in their modification of Rac1 and Ras. The data suggest a model where differences in GTPase localization dictate cellular responses to intoxication and highlight the importance of autoprocessing in the function of TcsL. IMPORTANCE Clostridium sordellii is a bacterium that can infect humans and cause serious disease and death. The principle virulence factor associated with clinical symptoms is a large protein toxin known as lethal toxin. The mechanism of lethal-toxin intoxication is assumed to be similar to that of the homologous toxins from C. difficile, but very few studies have been done in the context of endothelial cells, a relevant target in C. sordellii infections. This study was designed to test the role of the lethal-toxin enzymatic activities and membrane localization in endothelial cell toxicity and host substrate modification. PMID:27303685

  20. An offset-fed reflector antenna with an axially symmetric main reflector

    NASA Astrophysics Data System (ADS)

    Chang, D.-C.; Rusch, W. V. T.

    1984-11-01

    A design method for an offset-fed, dual reflector antenna (Cassegrain type or Gregorian type) system with an axisymmetric main reflector is presented. Geometrical optics (GO) and the geometrical theory of diffraction (GTD) are used to find the surface-current density on the main reflector. A modified Jacobi-Bessel series (JBS) method is used to find the far-field pattern for the physical optics (PO) integral. In the defocused mode of operation, a new technique is developed to find the reflection point on the subreflector corresponding to the defocused feed and a general field point on the main reflector. Two sample systems are designed.

  1. Reservoir technology research at Lawrence Berkeley Laboratory

    SciTech Connect

    Lippmann, M.J.

    1987-04-01

    The research being carried out at LBL as part of DOE/GTD's Reservoir Technology Program includes field, theoretical and modeling activities. The purpose is to develop, improve and validate methods and instrumentation to: (1) determine geothermal reservoir parameters, (2) detect and characterize reservoir fractures and boundaries, and (3) identify and evaluate the importance of reservoir processes. The ultimate objective of this work is to advance the state-of-the-art for characterizing geothermal reservoirs and evaluating their productive capacity and longevity under commercial exploitation. LBL's FY1986 accomplishments, FY1987 progress to date, and possible future activities under DOE's Reservoir Technology Program are discussed.

  2. Constitutive parameter measurements of lossy materials

    NASA Technical Reports Server (NTRS)

    Dominek, A.; Park, A.

    1989-01-01

    The electrical constitutive parameters of lossy materials are considered. A discussion of the NRL arch for lossy coatings is presented involving analytical analyses of the reflected field using the geometrical theory of diffraction (GTD) and physical optics (PO). The actual values for these parameters can be obtained through a traditional transmission technique which is examined from an error analysis standpoint. Alternate sample geometries are suggested for this technique to reduce sample tolerance requirements for accurate parameter determination. The performance for one alternate geometry is given.

  3. Effects of Solutioning on the Dissolution and Coarsening of γ' Precipitates in a Nickel-Based Superalloy

    NASA Astrophysics Data System (ADS)

    Wang, Xiaomeng; Zhou, Yu; Zhao, Zihua; Zhang, Zheng

    2015-04-01

    The dissolution and the coarsening of the γ' precipitates in a nickel-based superalloy GTD-111 solutionized under various solution heat treatment conditions were investigated. The γ' solvus temperature for the GTD-111 superalloy was about 1180.79 °C obtained by differential scanning calorimetry test. The dissolution and the coarsening of γ' in the dendrite core were simultaneously observed, but the γ' precipitates in the interdendritics only occurred to coarsen under the condition of 1125 °C/2 h. The γ' dissolution, including dendrite core and interdendritics, gradually played a dominant role in the competition between the dissolution and the coarsening of γ' during the solutioning with the increase of solution temperature and holding time, indicating that the elastic strain field of the alloy gradually reduced. The solution condition of 1225 °C/6 h or 1250 °C/2 h was the optimal solutioning schedule than the other schedules. For a lower solution temperature, the volume fraction of primary γ' precipitates can faster reach its equilibrium value which is larger than that for a higher solution temperature. With the increase of holding time, the γ' dissolution rate continuously decreased, and the dissolution activation energy of γ' gradually increased.

  4. Complete molar pregnancy in postmenopausal women.

    PubMed

    Begum, Jasmina; Palai, Pallavee; Ghose, Seetesh

    2016-01-01

    Gestational trophoblastic disease (GTD) is an abnormal proliferation of trophoblastic tissue during pregnancy. It is a disease of reproductive age, and a few cases have also been seen in women with advanced age, although it is extremely rare in postmenopausal women. Here, we describe an uncommon case of complete hydatidiform mole (CHM) in a postmenopausal woman, who has presented to us with complaints of bleeding per vagina, vomiting with 22 weeks size gravid uterus. Ultrasound finding along with raised serum beta-human chorionic gonadotropin (β-HCG) 400,000 mIU/ml suggested the diagnosis of CHM. In view of postmenopausal status and future risk of postmolar gestational trophoblastic neoplasia, we performed a total abdominal hysterectomy. Uterus was 20 cm × 15 cm × 15 cm filled with cystic, grapes such as vesicles. Microscopic examination demonstrated generalized trophoblastic proliferation with hydropic degenerated villi suggested of benign CHM. Follow-up showed steady fall in serum β-HCG level and no evidence of any residual disease. A suspicion of GTD should be kept in mind while evaluating a patient with peri- or post-menopausal bleeding so that it will prevent a delay in diagnosis and treatment. PMID:27499598

  5. Modeling Cyclic Phase Change and Energy Storage in Solar Heat Receivers

    NASA Technical Reports Server (NTRS)

    Hall, Carsie A., III; Glakpe, Emmanuel K.; Cannon, Joseph N.; Kerslake, Thomas W.

    1997-01-01

    Numerical results pertaining to cyclic melting and freezing of an encapsulated phase change material (PCM), integrated into a solar heat receiver, have been reported. The cyclic nature of the present melt/freeze problem is relevant to latent heat thermal energy storage (LHTES) systems used to power solar Brayton engines in microgravity environments. Specifically, a physical and numerical model of the solar heat receiver component of NASA Lewis Research Center's Ground Test Demonstration (GTD) project was developed and results compared with available experimental data. Multi-conjugate effects such as the convective fluid flow of a low-Prandtl-number fluid, coupled with thermal conduction in the phase change material, containment tube and working fluid conduit were accounted for in the model. A single-band thermal radiation model was also included to quantify reradiative energy exchange inside the receiver and losses through the aperture. The eutectic LiF-CaF2 was used as the phase change material (PCM) and a mixture of He/Xe was used as the working fluid coolant. A modified version of the computer code HOTTube was used to generate results for comparisons with GTD data for both the subcooled and two-phase regimes. While qualitative trends were in close agreement for the balanced orbit modes, excellent quantitative agreement was observed for steady-state modes.

  6. Experimental Data for Two Different Alternator Configurations in a Solar Brayton Power System

    NASA Technical Reports Server (NTRS)

    Mason, Lee S.; Shaltens, Richard K.; Espinosa, William D.

    1997-01-01

    A solar dynamic (SD) space power system has been under test at the NASA Lewis Research Center since 1994. The SD Ground Test Demonstration (GTD) system includes a solar concentrator, heat receiver with thermal energy storage, Brayton power conversion unit, and radiator installed in a thermal-vacuum chamber with a solar simulator. The Brayton unit has been operated with two different turboalternator compressor (TAC) assemblies, one which included a Rice Lundell alternator and another which incorporated a permanent magnet (PM) alternator. The Rice alternator was part of the mini-Brayton rotating unit, designed and built during the 1970's and refurbished for the GTD. The PM TAC was a development unit from the Joint US/Russian SD Flight Project. This paper highlights the operational differences (and similarities) between the Rice and PM TAC configurations including a comparative evaluation of startup characteristics and operating performance. The two alternator configurations were tested under similar thermal conditions, as an interchangeable component within the SD system. The electrical characteristics of the two units, however, dictated the use of significantly different power conditioning and control strategies. The electrical control architectures are described and compared. Test data are presented on TAC startup and system operating performance for both configurations.

  7. Analyses of the temporal dynamics of fungal communities colonizing the healthy wood tissues of esca leaf-symptomatic and asymptomatic vines.

    PubMed

    Bruez, Emilie; Vallance, Jessica; Gerbore, Jonathan; Lecomte, Pascal; Da Costa, Jean-Pierre; Guerin-Dubrana, Lucia; Rey, Patrice

    2014-01-01

    Esca, a Grapevine Trunk Disease (GTD), is of major concern for viticulture worldwide. Our study compares the fungal communities that inhabit the wood tissues of vines that expressed or not foliar esca-symptoms. The trunk and rootstock tissues were apparently healthy, whether the 10 year-old plants were symptomatic or not. The only difference was in the cordon, which contained white rot, a typical form of esca, in 79% of symptomatic plants. Observations over a period of one year using a fingerprint method, Single Strand Conformation Polymorphism (SSCP), and the ITS-DNA sequencing of cultivable fungi, showed that shifts occurred in the fungal communities colonizing the healthy wood tissues. However, whatever the sampling time, spring, summer, autumn or winter, the fungi colonizing the healthy tissues of asymptomatic or symptomatic plants were not significantly different. Forty-eight genera were isolated, with species of Hypocreaceae and Botryosphaeriaceae being the most abundant species. Diverse fungal assemblages, made up of potentially plant-pathogenic and -protective fungi, colonized these non-necrotic tissues. Some fungi, possibly involved in GTD, inhabited the non-necrotic wood of young plants, but no increase in necrosis areas was observed over the one-year period. PMID:24788412

  8. Propagation model for the Land Mobile Satellite channel in urban environments

    NASA Technical Reports Server (NTRS)

    Sforza, M.; Dibernardo, G.; Cioni, R.

    1993-01-01

    This paper presents the major characteristics of a simulation package capable of performing a complete narrow and wideband analysis of the mobile satellite communication channel in urban environments for any given orbital configuration. The wavelength-to-average urban geometrical dimension ratio has required the use of the Geometrical Theory of Diffraction (GTD). For the RF frequency range, the model has been designed to be (1 up to 60 GHz) extended to include effects of non-perfect conductivity and surface roughness. Taking advantage of the inherent capabilities of such a high frequency method, we are able to provide a complete description of the electromagnetic field at the mobile terminal. Using the information made available at the ray-tracer and GTD solver outputs, the Land Mobile Satellite (LMS) urban model can also give a detailed description of the communication channel in terms of power delay profiles, Doppler spectra, channel scattering functions, and so forth. Statistical data, e.g. cumulative distribution functions, level crossing rates or distributions of fades are also provided. The user can access the simulation tool through a Design-CAD user-friendly interface by means of which she can effectively design her own urban layout and run consequently all the envisaged routines. The software is optimized in its execution time so that numerous runs can be achieved in a considerably short time.

  9. Coordinated recruitment of Spir actin nucleators and myosin V motors to Rab11 vesicle membranes

    PubMed Central

    Pylypenko, Olena; Welz, Tobias; Tittel, Janine; Kollmar, Martin; Chardon, Florian; Malherbe, Gilles; Weiss, Sabine; Michel, Carina Ida Luise; Samol-Wolf, Annette; Grasskamp, Andreas Till; Hume, Alistair; Goud, Bruno; Baron, Bruno; England, Patrick; Titus, Margaret A; Schwille, Petra; Weidemann, Thomas

    2016-01-01

    There is growing evidence for a coupling of actin assembly and myosin motor activity in cells. However, mechanisms for recruitment of actin nucleators and motors on specific membrane compartments remain unclear. Here we report how Spir actin nucleators and myosin V motors coordinate their specific membrane recruitment. The myosin V globular tail domain (MyoV-GTD) interacts directly with an evolutionarily conserved Spir sequence motif. We determined crystal structures of MyoVa-GTD bound either to the Spir-2 motif or to Rab11 and show that a Spir-2:MyoVa:Rab11 complex can form. The ternary complex architecture explains how Rab11 vesicles support coordinated F-actin nucleation and myosin force generation for vesicle transport and tethering. New insights are also provided into how myosin activation can be coupled with the generation of actin tracks. Since MyoV binds several Rab GTPases, synchronized nucleator and motor targeting could provide a common mechanism to control force generation and motility in different cellular processes. DOI: http://dx.doi.org/10.7554/eLife.17523.001 PMID:27623148

  10. Radiation Characteristics of Cavity Backed Aperture Antennas in Finite Ground Plane Using the Hybrid FEM/MoM Technique and Geometrical Theory of Diffraction

    NASA Technical Reports Server (NTRS)

    Reddy, C. J.; Deshpande, M. D.; Cockrell, C. R.; Beck, F. B.

    1996-01-01

    A technique using hybrid Finite Element Method (FEM)/Method of Moments (MoM), and Geometrical Theory of Diffraction (GTD) is presented to analyze the radiation characteristics of cavity fed aperture antennas in a finite ground plane. The cavity which excites the aperture is assumed to be fed by a cylindrical transmission line. The electromagnetic (EM) fields inside the cavity are obtained using FEM. The EM fields and their normal derivatives required for FEM solution are obtained using (1) the modal expansion in the feed region and (2) the MoM for the radiating aperture region(assuming an infinite ground plane). The finiteness of the ground plane is taken into account using GTD. The input admittance of open ended circular, rectangular, and coaxial line radiating into free space through an infinite ground plane are computed and compared with earlier published results. Radiation characteristics of a coaxial cavity fed circular aperture in a finite rectangular ground plane are verified with experimental results.

  11. Coordinated recruitment of Spir actin nucleators and myosin V motors to Rab11 vesicle membranes.

    PubMed

    Pylypenko, Olena; Welz, Tobias; Tittel, Janine; Kollmar, Martin; Chardon, Florian; Malherbe, Gilles; Weiss, Sabine; Michel, Carina Ida Luise; Samol-Wolf, Annette; Grasskamp, Andreas Till; Hume, Alistair; Goud, Bruno; Baron, Bruno; England, Patrick; Titus, Margaret A; Schwille, Petra; Weidemann, Thomas; Houdusse, Anne; Kerkhoff, Eugen

    2016-01-01

    There is growing evidence for a coupling of actin assembly and myosin motor activity in cells. However, mechanisms for recruitment of actin nucleators and motors on specific membrane compartments remain unclear. Here we report how Spir actin nucleators and myosin V motors coordinate their specific membrane recruitment. The myosin V globular tail domain (MyoV-GTD) interacts directly with an evolutionarily conserved Spir sequence motif. We determined crystal structures of MyoVa-GTD bound either to the Spir-2 motif or to Rab11 and show that a Spir-2:MyoVa:Rab11 complex can form. The ternary complex architecture explains how Rab11 vesicles support coordinated F-actin nucleation and myosin force generation for vesicle transport and tethering. New insights are also provided into how myosin activation can be coupled with the generation of actin tracks. Since MyoV binds several Rab GTPases, synchronized nucleator and motor targeting could provide a common mechanism to control force generation and motility in different cellular processes. PMID:27623148

  12. Successful treatment of a persistent mole with myometrial invasion by direct injection of methotrexate.

    PubMed

    Su, W H; Wang, P H; Chang, S P

    2001-01-01

    For patients with persistent or invasive gestational trophoblastic disease (GTD), systemic injection of chemotherapy is the treatment of choice if fertility is to be preserved. To prevent serious adverse effects after systemic use and possibly achieve better effects, direct local injection of chemotherapy into the tumor site, especially when in the myometrium, seems a reasonable alternative. A patient with a persistent molar pregnancy with myometrial invasion is presented. A plateau of beta-hCG (human chorionic gonadotropin) level around 550 mIU/mL was noticed for three weeks though systemic methotrexate (MTX) injection and repeat suction curettage had been performed. During the same period, a well-defined invasive complex with multiple vesicles in the myometrium was documented using transvaginal ultrasound (TVUS). Sonar-guided injection to the tumor using 50 mg MTX was performed uneventfully. An obvious shrinkage of the mass and declining beta-hCG level were demonstrated after the procedure. The patient restored her menses after the operation and a fertility evaluation including serial beta-hCG levels and hysterosalpingography showed them to be within the reference ranges. The successful outcome of this case encouraged us to treat localized invasive GTD using direct injection of MTX with the guidance of TVUS. Since no identical cases were found in our review of the English literature, more cases and similar regimens are needed to establish the safety and efficacy of this procedure.

  13. Complete molar pregnancy in postmenopausal women

    PubMed Central

    Begum, Jasmina; Palai, Pallavee; Ghose, Seetesh

    2016-01-01

    Gestational trophoblastic disease (GTD) is an abnormal proliferation of trophoblastic tissue during pregnancy. It is a disease of reproductive age, and a few cases have also been seen in women with advanced age, although it is extremely rare in postmenopausal women. Here, we describe an uncommon case of complete hydatidiform mole (CHM) in a postmenopausal woman, who has presented to us with complaints of bleeding per vagina, vomiting with 22 weeks size gravid uterus. Ultrasound finding along with raised serum beta-human chorionic gonadotropin (β-HCG) 400,000 mIU/ml suggested the diagnosis of CHM. In view of postmenopausal status and future risk of postmolar gestational trophoblastic neoplasia, we performed a total abdominal hysterectomy. Uterus was 20 cm × 15 cm × 15 cm filled with cystic, grapes such as vesicles. Microscopic examination demonstrated generalized trophoblastic proliferation with hydropic degenerated villi suggested of benign CHM. Follow-up showed steady fall in serum β-HCG level and no evidence of any residual disease. A suspicion of GTD should be kept in mind while evaluating a patient with peri- or post-menopausal bleeding so that it will prevent a delay in diagnosis and treatment. PMID:27499598

  14. Eco-hydrology: Groundwater flow and site factors in plant ecology

    NASA Astrophysics Data System (ADS)

    Klijn, Frans; Witte, Jan-Philip M.

    Résumé En écologie végétale, le site est un concept central. Un site, c'est l'endroit où une espèce végétale ou une communauté de plantes se développe le site assure un ensemble de conditions dans lesquelles elles vivent. Dans un matériau homogène à l'origine, l'écoulement gravitaire d'une nappe influence les conditions du site par l'intermédiaire de la distribution spatiale des nutriments et d'autres composés chimiques associés. Les remontées d'eau peuvent tout spécialement produire et maintenir les conditions du site essentielles pour différentes espèces et communautés de plantes relativement rares. Les écologues ont porté une attention accrue à ces remontées d'eau, en sorte qu'une coopération avec les hydrologues en a résulté, avec l'émergence d'une discipline propre, l'éco-hydrologie, à la limite des deux domaines scientifiques et liée au concept de site. Aux Pays-Bas, une classification des types d'eau, basée sur l'histoire de l'eau souterraine à proximité de la surface, a été mise en oeuvre pour constituer une base nationale de données géographiques sur les remontées d'eau d'intérêt écologique. Des analyses des correspondances des données de cette base, portant sur l'existence de certaines espèces de plantes, montrent que dans les sols sableux pauvres du Pléistocène la remontée d'eau explique très bien la présence de certaines espèces et communautés, alors que, dans les plaines fluviales et les régions de polders à sols argileux riches, l'influence de la remontée d'eau est masquée par l'importance des caractéristiques des sols. En conclusion donc, certaines espèces de plantes peuvent être utilisées comme des indicateurs de la remontée d'eau dans des diagnostiques et des levés de terrain rapides, mais à condition de prendre en permanence des précautions sur les limites de l'approche. Resumen En ecología botánica un concepto de gran importancia es el de emplazamiento, definido como el lugar que

  15. Summary of the planning, management, and evaluation process for the Geothermal Program Review VI conference

    SciTech Connect

    Not Available

    1988-10-01

    The purpose of this document is to present an overview of the planning, facilitation, and evaluation process used to conduct the Geothermal Program Review VI (PR VI) conference. This document was also prepared to highlight lessons learned from PR VI and, by utilizing the evaluation summaries and recommendations, be used as a planning tool for PR VII. The conference, entitled Beyond Goals and Objectives,'' was sponsored by the US Department of Energy's (DOE) Geothermal Technology Division (GTD), PR VI was held in San Francisco, California on April 19--21, 1988 and was attended by 127 participants. PR VI was held in conjunction with the National Geothermal Association's (NGA) Industry Round Table. This document presents a brief summary of the activities, responsibilities, and resources for implementing the PR VI meeting and provides recommendations, checklists, and a proposed schedule for assisting in planning PR VII.

  16. Explosive cavitation in superheated liquid argon.

    PubMed

    Vinogradov, V E; Pavlov, P A; Baidakov, V G

    2008-06-21

    The kinetics of explosive boiling-up of liquid argon has been investigated at negative pressures created by the reflection of a compression pulse 3-5 mus long from the free surface of a liquid by the method of liquid pulse heating on a thin platinum wire (with a rate of temperature increase of about 1 Kmus). The limiting superheats T(*) (stretches p(*)), the effective nucleation rate J(*), and the derivative G(T)=(d ln JdT)(T=T(*) ) have been determined by experimental data on the thermal perturbation of a wire probe and the results of solution of the problem on the initial stage of explosive boiling-up of a liquid. The experimental data are compared with homogeneous nucleation theory. PMID:18570511

  17. Computer Analysis of Electromagnetic Field Exposure Hazard for Space Station Astronauts during Extravehicular Activity

    NASA Technical Reports Server (NTRS)

    Hwu, Shian U.; Kelley, James S.; Panneton, Robert B.; Arndt, G. Dickey

    1995-01-01

    In order to estimate the RF radiation hazards to astronauts and electronics equipment due to various Space Station transmitters, the electric fields around the various Space Station antennas are computed using the rigorous Computational Electromagnetics (CEM) techniques. The Method of Moments (MoM) was applied to the UHF and S-band low gain antennas. The Aperture Integration (AI) method and the Geometrical Theory of Diffraction (GTD) method were used to compute the electric field intensities for the S- and Ku-band high gain antennas. As a result of this study, The regions in which the electric fields exceed the specified exposure levels for the Extravehicular Mobility Unit (EMU) electronics equipment and Extravehicular Activity (EVA) astronaut are identified for various Space Station transmitters.

  18. Scattering Effects of Solar Panels on Space Station Antenna Performance

    NASA Technical Reports Server (NTRS)

    Panneton, Robert J.; Ngo, John C.; Hwu, Shian U.; Johnson, Larry A.; Elmore, James D.; Lu, Ba P.; Kelley, James S.

    1994-01-01

    Characterizing the scattering properties of the solar array panels is important in predicting Space Station antenna performance. A series of far-field, near-field, and radar cross section (RCS) scattering measurements were performed at S-Band and Ku-Band microwave frequencies on Space Station solar array panels. Based on investigation of the measured scattering patterns, the solar array panels exhibit similar scattering properties to that of the same size aluminum or copper panel mockup. As a first order approximation, and for worse case interference simulation, the solar array panels may be modeled using perfect reflecting plates. Numerical results obtained using the Geometrical Theory of Diffraction (GTD) modeling technique are presented for Space Station antenna pattern degradation due to solar panel interference. The computational and experimental techniques presented in this paper are applicable for antennas mounted on other platforms such as ship, aircraft, satellite, and space or land vehicle.

  19. Reducing long-term reservoir performance uncertainty

    SciTech Connect

    Lippmann, M.J.

    1988-04-01

    Reservoir performance is one of the key issues that have to be addressed before going ahead with the development of a geothermal field. In order to select the type and size of the power plant and design other surface installations, it is necessary to know the characteristics of the production wells and of the produced fluids, and to predict the changes over a 10--30 year period. This is not a straightforward task, as in most cases the calculations have to be made on the basis of data collected before significant fluid volumes have been extracted from the reservoir. The paper describes the methodology used in predicting the long-term performance of hydrothermal systems, as well as DOE/GTD-sponsored research aimed at reducing the uncertainties associated with these predictions. 27 refs., 1 fig.

  20. Electromagnetic backscattering by corner reflectors

    NASA Technical Reports Server (NTRS)

    Balanis, C. A.; Griesser, T.

    1986-01-01

    The Geometrical Theory of Diffraction (GTD), which supplements Geometric Optics (GO), and the Physical Theory of Diffraction (PTD), which supplements Physical Optics (PO), are used to predict the backscatter cross sections of dihedral corner reflectors which have right, obtuse, or acute included angles. These theories allow individual backscattering mechanisms of the dihedral corner reflectors to be identified and provide good agreement with experimental results in the azimuthal plane. The advantages and disadvantages of the geometrical and physical theories are discussed in terms of their accuracy, usefulness, and complexity. Numerous comparisons of analytical results with experimental data are presented. While physical optics alone is more accurate and more useful than geometrical optics alone, the combination of geometrical optics and geometrical diffraction seems to out perform physical optics and physical diffraction when compared with experimental data, especially for acute angle dihedral corner reflectors.

  1. Analysis of three-dimensional-cavity-backed aperture antennas using a Combined Finite Element Method/Method of Moments/Geometrical Theory of Diffraction technique

    NASA Technical Reports Server (NTRS)

    Reddy, C. J.; Deshpande, M. D.; Cockrell, C. R.; Beck, F. B.

    1995-01-01

    A combined finite element method (FEM) and method of moments (MoM) technique is presented to analyze the radiation characteristics of a cavity-fed aperture in three dimensions. Generalized feed modeling has been done using the modal expansion of fields in the feed structure. Numerical results for some feeding structures such as a rectangular waveguide, circular waveguide, and coaxial line are presented. The method also uses the geometrical theory of diffraction (GTD) to predict the effect of a finite ground plane on radiation characteristics. Input admittance calculations for open radiating structures such as a rectangular waveguide, a circular waveguide, and a coaxial line are shown. Numerical data for a coaxial-fed cavity with finite ground plane are verified with experimental data.

  2. Design considerations for the beam-waveguide retrofit of a ground antenna station

    NASA Technical Reports Server (NTRS)

    Veruttipong, T.; Withington, J.; Galindo-Israel, V.; Imbriale, W.; Bathker, D.

    1986-01-01

    Retrofitting an antenna that was originally designed without a beam waveguide introduces special difficulties because it is desirable to minimize alteration of the original mechanical truss work and to image the actual feed without distortion at the focal point of the dual-shaped reflector. To obtain an acceptable image, certain Geometrical Optics (GO) design criteria are followed as closely as possible. The problems associated with applying these design criteria to a 34-meter dual-shaped DSN (Deep Space Network) antenna are discussed. The use of various diffraction analysis techniques in the design process is also discussed. GTD and FFT algorithms are particularly necessary at the higher frequencies, while Physical Optics and Spherical Wave Expansions proved necessary at the lower frequencies.

  3. DSS 43 antenna gain analysis for Voyager Uranus encounter: 8.45-GHz radio science data correction

    NASA Technical Reports Server (NTRS)

    Slobin, S. D.; Imbriale, W. A.

    1987-01-01

    A malfunction of the Deep Space Network (DSN) 64-meter antenna in Australia forced the antenna to operate with a mispositioned subreflector during the Voyager Uranus encounter period (January 24, 1986). Because of changing main reflector shape and quadripod position as a function of elevation angle, the antenna gain and pointing were not as expected, and the 8.45 GHz received signal level changed during the pass. The study described here used the Geometrical Theory of Diffraction (GTD) analysis to determine actual antenna gain and pointing during that period in an attempt to reconstruct the radio science data. It is found that the 1.4 dB of signal variation can be accounted for by antenna geometry changes and pointing error. Suggested modifications to the values measured during the pass are presented. Additionally, an extremely useful tool for the analysis of gravity deformed reflectors was developed for use in future antenna design and analysis projects.

  4. Thermodynamic geometry of black holes in f( R) gravity

    NASA Astrophysics Data System (ADS)

    Soroushfar, Saheb; Saffari, Reza; Kamvar, Negin

    2016-09-01

    In this paper, we consider three types (static, static charged, and rotating charged) of black holes in f( R) gravity. We study the thermodynamical behavior, stability conditions, and phase transition of these black holes. It is shown that the number and type of phase transition points are related to different parameters, which shows the dependency of the stability conditions to these parameters. Also, we extend our study to different thermodynamic geometry methods (Ruppeiner, Weinhold, and GTD). Next, we investigate the compatibility of curvature scalar of geothermodynamic methods with phase transition points of the above black holes. In addition, we point out the effect of different values of the spacetime parameters on the stability conditions of mentioned black holes.

  5. A Segment of 97 Amino Acids within the Translocation Domain of Clostridium difficile Toxin B Is Essential for Toxicity

    PubMed Central

    Zhang, Yongrong; Shi, Lianfa; Li, Shan; Yang, Zhiyong; Standley, Clive; Yang, Zhong; ZhuGe, Ronghua; Savidge, Tor; Wang, Xiaoning; Feng, Hanping

    2013-01-01

    Clostridium difficile toxin B (TcdB) intoxicates target cells by glucosylating Rho GTPases. TcdB (269 kDa) consists of at least 4 functional domains including a glucosyltransferase domain (GTD), a cysteine protease domain (CPD), a translocation domain (TD), and a receptor binding domain (RBD). The function and molecular mode of action of the TD, which is the largest segment of TcdB and comprises nearly 50% of the protein, remain largely unknown. Here we show that a 97-amino-acid segment (AA1756 – 1852, designated as ?97 or D97), located in the C-terminus of the TD and adjacent to the RBD, is essential for the cellular activity of TcdB. Deletion of this segment in TcdB (designated as TxB-D97), did not adversely alter toxin enzymatic activities or its cellular binding and uptake capacity. TxB-D97 bound to and entered cells in a manner similar to TcdB holotoxin. Both wild type and mutant toxins released their GTDs similarly in the presence of inositol hexakisphosphate (InsP6), and showed a similar glucosyltransferase activity in a cell-free glucosylating assay. Despite these similarities, the cytotoxic activity of TxB-D97 was reduced by more than 5 logs compared to wild type toxin, supported by the inability of TxB-D97 to glucosylate Rac1 of target cells. Moreover, the mutant toxin failed to elicit tumor necrosis factor alpha (TNF-α) in macrophages, a process dependent on the glucosyltransferase activity of the toxin. Cellular fractionation of toxin-exposed cells revealed that TxB-D97 was unable to efficiently release the GTD into cytosol. Thereby, we conclude the 97-amino-acid region of the TD C-terminus of TcdB adjacent to the RBD, is essential for the toxicity of TcdB. PMID:23484044

  6. Generalized Tumor Dose for Treatment Planning Decision Support

    NASA Astrophysics Data System (ADS)

    Zuniga, Areli A.

    Modern radiation therapy techniques allow for improved target conformity and normal tissue sparing. These highly conformal treatment plans have allowed dose escalation techniques increasing the probability of tumor control. At the same time this conformation has introduced inhomogeneous dose distributions, making delivered dose characterizations more difficult. The concept of equivalent uniform dose (EUD) characterizes a heterogeneous dose distribution within irradiated structures as a single value and has been used in biologically based treatment planning (BBTP); however, there are no substantial validation studies on clinical outcome data supporting EUD's use and therefore has not been widely adopted as decision-making support. These highly conformal treatment plans have also introduced the need for safety margins around the target volume. These margins are designed to minimize geometrical misses, and to compensate for dosimetric and treatment delivery uncertainties. The margin's purpose is to reduce the chance of tumor recurrence. This dissertation introduces a new EUD formulation designed especially for tumor volumes, called generalized Tumor Dose (gTD). It also investigates, as a second objective, margins extensions for potential improvements in local control while maintaining or minimizing toxicity. The suitability of gTD to rank LC was assessed by means of retrospective studies in a head and neck (HN) squamous cell carcinoma (SCC) and non-small cell lung cancer (NSCLC) cohorts. The formulation was optimized based on two datasets (one of each type) and then, model validation was assessed on independent cohorts. The second objective of this dissertation was investigated by ranking the probability of LC of the primary disease adding different margin sizes. In order to do so, an already published EUD formula was used retrospectively in a HN and a NSCLC datasets. Finally, recommendations for the viability to implement this new formulation into a routine treatment

  7. Recent advances in semi-analytical scattering models for NDT simulation

    NASA Astrophysics Data System (ADS)

    Darmon, M.; Chatillon, S.; Mahaut, S.; Calmon, P.; Fradkin, L. J.; Zernov, V.

    2011-01-01

    For several years, CEA-LIST and partners have been developing ultrasonic simulation tools with the aim of modelling non-destructive evaluation. The existing ultrasonic modules allow us to simulate fully real ultrasonic inspection scenarios in a range of applications which requires the computation of the propagated beam, as well as its interaction with flaws. To fulfil requirements of an intensive use (for parametric studies), the choice has been made to adopt mainly analytical approximate or exact methods to model the scattering of ultrasound by flaws. The applied analytical theories (Kirchhoff and Born approximations, GTD, SOV...) were already described in previous GDR communication. Over the years, this "semi-analytical" approach has been enriched by adaptations and improvements of the existing models or by new models, in order to extend the applicability of the simulation tools. This paper is devoted to the following recent advances performed in the framework of this approach: The SOV method based on the exact analytical model for the scattering from a cylindrical cavity has been extended in 3D to account for field variations along the cylinder. This new 3D model leads to an improvement in simulation of small side-drilled holes. Concerning the geometrical theories of diffraction (GTD), subroutines for calculation of the 2D wedge diffraction coefficients (for bulk or Rayleigh incident waves) have been developed by the Waves and Fields Group and uniform corrections (UAT and UTD) are under investigation. Modelling of the contribution of the head wave and creeping wave to the echoes arising from a wedge. Numerous experimental validations of the developed models are provided. New possibilities offered by these new developments are emphasized.

  8. Axial, scalar, and tensor charges of the nucleon from 2 +1 +1 -flavor Lattice QCD

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Tanmoy; Cirigliano, Vincenzo; Cohen, Saul D.; Gupta, Rajan; Lin, Huey-Wen; Yoon, Boram; Precision Neutron Decay Matrix Elements Pndme Collaboration

    2016-09-01

    We present results for the isovector axial, scalar, and tensor charges gAu -d , gSu -d, and gTu -d of the nucleon needed to probe the Standard Model and novel physics. The axial charge is a fundamental parameter describing the weak interactions of nucleons. The scalar and tensor charges probe novel interactions at the TeV scale in neutron and nuclear β -decays, and the flavor-diagonal tensor charges gTu, gTd, and gTs are needed to quantify the contribution of the quark electric dipole moment (EDM) to the neutron EDM. The lattice-QCD calculations were done using nine ensembles of gauge configurations generated by the MILC Collaboration using the highly improved staggered quarks action with 2 +1 +1 dynamical flavors. These ensembles span three lattice spacings a ≈0.06 ,0.09 , and 0.12 fm and light-quark masses corresponding to the pion masses Mπ≈135 ,225 , and 315 MeV. High-statistics estimates on five ensembles using the all-mode-averaging method allow us to quantify all systematic uncertainties and perform a simultaneous extrapolation in the lattice spacing, lattice volume, and light-quark masses for the connected contributions. Our final estimates, in the MS ¯ scheme at 2 GeV, of the isovector charges are gAu -d=1.195 (33 )(20 ) , gSu -d=0.97 (12 )(6 ), and gTu -d=0.987 (51 )(20 ) . The first error includes statistical and all systematic uncertainties except that due to the extrapolation Ansatz, which is given by the second error estimate. Combining our estimate for gSu -d with the difference of light quarks masses (md-mu)QCD=2.67 (35 ) MeV given by the Flavor Lattice Average Group, we obtain (MN-MP)QCD=2.59 (49 ) MeV . Estimates of the connected part of the flavor-diagonal tensor charges of the proton are gTu=0.792 (42 ) and gTd=-0.194 (14 ). Combining our new estimates with precision low-energy experiments, we present updated constraints on novel scalar and tensor interactions, ɛS ,T, at the TeV scale.

  9. Affordable Development and Demonstration of a Small NTR Engine and Stage: How Small is Big Enough?

    NASA Technical Reports Server (NTRS)

    Borowski, Stanley K.; Sefcik, Robert J.; Fittje, James E.; McCurdy, David R.; Qualls, Arthur L.; Schnitzler, Bruce G.; Werner, James E.; Weitzberg (Abraham); Joyner, Claude R.

    2015-01-01

    The Nuclear Thermal Rocket (NTR) derives its energy from fission of uranium-235 atoms contained within fuel elements that comprise the engine's reactor core. It generates high thrust and has a specific impulse potential of approximately 900 seconds - a 100% increase over today's best chemical rockets. The Nuclear Thermal Propulsion (NTP) project, funded by NASA's AES program, includes five key task activities: (1) Recapture, demonstration, and validation of heritage graphite composite (GC) fuel (selected as the "Lead Fuel" option); (2) Engine Conceptual Design; (3) Operating Requirements Definition; (4) Identification of Affordable Options for Ground Testing; and (5) Formulation of an Affordable Development Strategy. During FY'14, a preliminary DDT&E plan and schedule for NTP development was outlined by GRC, DOE and industry that involved significant system-level demonstration projects that included GTD tests at the NNSS, followed by a FTD mission. To reduce cost for the GTD tests and FTD mission, small NTR engines, in either the 7.5 or 16.5 klbf thrust class, were considered. Both engine options used GC fuel and a "common" fuel element (FE) design. The small approximately 7.5 klbf "criticality-limited" engine produces approximately 157 megawatts of thermal power (MWt) and its core is configured with parallel rows of hexagonal-shaped FEs and tie tubes (TTs) with a FE to TT ratio of approximately 1:1. The larger approximately 16.5 klbf Small Nuclear Rocket Engine (SNRE), developed by LANL at the end of the Rover program, produces approximately 367 MWt and has a FE to TT ratio of approximately 2:1. Although both engines use a common 35 inch (approximately 89 cm) long FE, the SNRE's larger diameter core contains approximately 300 more FEs needed to produce an additional 210 MWt of power. To reduce the cost of the FTD mission, a simple "1-burn" lunar flyby mission was considered to reduce the LH2 propellant loading, the stage size and complexity. Use of existing and

  10. Crack initiation modeling of a directionally-solidified nickel-base superalloy

    NASA Astrophysics Data System (ADS)

    Gordon, Ali Page

    Combustion gas turbine components designed for application in electric power generation equipment are subject to periodic replacement as a result of cracking, damage, and mechanical property degeneration that render them unsafe for continued operation. In view of the significant costs associated with inspecting, servicing, and replacing damaged components, there has been much interest in developing models that not only predict service life, but also estimate the evolved microstructural state of the material. This thesis explains manifestations of microstructural damage mechanisms that facilitate fatigue crack nucleation in a newly-developed directionally-solidified (DS) Ni-base superalloy components exposed to elevated temperatures and high stresses. In this study, models were developed and validated for damage and life prediction using DS GTD-111 as the subject material. This material, proprietary to General Electric Energy, has a chemical composition and grain structure designed to withstand creep damage occurring in the first and second stage blades of gas-powered turbines. The service conditions in these components, which generally exceed 600°C, facilitate the onset of one or more damage mechanisms related to fatigue, creep, or environment. The study was divided into an empirical phase, which consisted of experimentally simulating service conditions in fatigue specimens, and a modeling phase, which entailed numerically simulating the stress-strain response of the material. Experiments have been carried out to simulate a variety of thermal, mechanical, and environmental operating conditions endured by longitudinally (L) and transversely (T) oriented DS GTD-111. Both in-phase and out-of-phase thermo-mechanical fatigue tests were conducted. In some cases, tests in extreme environments/temperatures were needed to isolate one or at most two of the mechanisms causing damage. Microstructural examinations were carried out via SEM and optical microscopy. A continuum

  11. Affordable Development and Demonstration of a Small NTR Engine and Stage: A Preliminary NASA, DOE, and Industry Assessment

    NASA Technical Reports Server (NTRS)

    Borowski, Stanley K.; Sefcik, Robert J.; Fittje, James E.; McCurdy, David R.; Qualls, Arthur L.; Schnitzler, Bruce G.; Werner, James E.; Weitzberg, Abraham; Joyner, Claude R.

    2015-01-01

    The Nuclear Thermal Rocket (NTR) represents the next evolutionary step in cryogenic liquid rocket engines. Deriving its energy from fission of uranium-235 atoms contained within fuel elements that comprise the engine's reactor core, the NTR can generate high thrust at a specific impulse of approx. 900 seconds or more - twice that of today's best chemical rockets. In FY'11, as part of the AISP project, NASA proposed a Nuclear Thermal Propulsion (NTP) effort that envisioned two key activities - "Foundational Technology Development" followed by system-level "Technology Demonstrations". Five near-term NTP activities identified for Foundational Technology Development became the basis for the NCPS project started in FY'12 and funded by NASA's AES program. During Phase 1 (FY'12-14), the NCPS project was focused on (1) Recapturing fuel processing techniques and fabricating partial length "heritage" fuel elements for the two candidate fuel forms identified by NASA and the DOE - NERVA graphite "composite" and the uranium dioxide (UO2) in tungsten "cermet". The Phase 1 effort also included: (2) Engine Conceptual Design; (3) Mission Analysis and Requirements Definition; (4) Identification of Affordable Options for Ground Testing; and (5) Formulation of an Affordable and Sustainable NTP Development Strategy. During FY'14, a preliminary plan for DDT&E was outlined by GRC, the DOE and industry for NASA HQ that involved significant system-level demonstration projects that included GTD tests at the NNSS, followed by a FTD mission. To reduce development costs, the GTD and FTD tests use a small, low thrust (approx. 7.5 or 16.5 klbf) engine. Both engines use graphite composite fuel and a "common" fuel element design that is scalable to higher thrust (approx. 25 klbf) engines by increasing the number of elements in a larger diameter core that can produce greater thermal power output. To keep the FTD mission cost down, a simple "1-burn" lunar flyby mission was considered along with

  12. Dynamics of Shengjini beach (Albania)

    NASA Astrophysics Data System (ADS)

    Gashi, Ferim; Nikolli, Pal

    2015-04-01

    Dynamics of Shengjini beach (Albania) Pal Nikolli , Ferim GASHI Through archaeological and historical data, presentations of ancient topographic, cartographic materials (topographic maps obtained at different periods from 1870 to 1990), aerial photographs (2007), satellite images (2014) and direct measurements, paper defines and analyzes the position of the coastline of Shengjini beach (Lezha) from century XVI until today. The coastline of the Shengjini city (port) to Drin River estuary is oriented north-south direction and is approximately 10.5 km long. This part of the coast is sandy and sediment comes mainly from the River Drin and distributed by currents along the coast. In this paper are make provision for the position of the coastline in the future and analyzed the possibilities of human intervention in the coastal environment , etc. This work forms the basis for the issuance of necessary data required for various projections at the coastal environment Shëngjini. Results of this study will have a significant impact on state policies for integrated management of the coastal zone in the study and development of tourism. Key words: GIS, Remonte Sennsing, cartography, management of coastal zone, tourism, environment.

  13. A Summary of Closed Brayton Cycle Development Activities at NASA

    NASA Technical Reports Server (NTRS)

    Mason, Lee S.

    2009-01-01

    NASA has been involved in the development of Closed Brayton Cycle (CBC) power conversion technology since the 1960's. CBC systems can be coupled to reactor, isotope, or solar heat sources and offer the potential for high efficiency, long life, and scalability to high power. In the 1960's and 1970's, NASA and industry developed the 10 kW Brayton Rotating Unit (BRU) and the 2 kW mini-BRU demonstrating technical feasibility and performance, In the 1980's, a 25 kW CBC Solar Dynamic (SD) power system option was developed for Space Station Freedom and the technology was demonstrated in the 1990's as part of the 2 kW SO Ground Test Demonstration (GTD). Since the early 2000's, NASA has been pursuing CBC technology for space reactor applications. Before it was cancelled, the Jupiter Icy Moons Orbiter (HMO) mission was considering a 100 kWclass CBC system coupled to a gas-cooled fission reactor. Currently, CBC technology is being explored for Fission Surface Power (FSP) systems to provide base power on the moon and Mars. These recent activities have resulted in several CBC-related technology development projects including a 50 kW Alternator Test Unit, a 20 kW Dual Brayton Test Loop, a 2 kW Direct Drive Gas Brayton Test Loop, and a 12 kW FSP Power Conversion Unit design.

  14. Effect of shadowing on electromagnetic scattering from rough ocean wavelike surfaces at small grazing angles

    SciTech Connect

    West, J.C.

    1997-03-01

    A hybrid moment-method/geometrical-theory-of-diffraction technique (MM/GTD) has been implemented to numerically calculate the electromagnetic scattering from one-dimensionally rough surfaces at extreme illumination angles (down to 0{degree} grazing). The hybrid approach allows the extension of the modeled scattering surface to infinity, avoiding the artificial edge diffraction that prevents use of the standard moment method at the smallest grazing angles. Numerical calculation of the backscattering from slightly rough large-scale surfaces approximating ocean wave features shows that roughness in strongly shadowed regions can contribute significantly to the total backscatter at vertical polarization. This is observed when the shadowing obstacle is several wavelengths high, and the magnitude of the shadow-region contribution does not depend on the radius-of-curvature of the shadowing feature. Strongly shadowed roughness does not significantly contribute to the backscatter at horizontal polarization, although weakly shadowed roughness near the incidence shadow boundary does. The calculations indicate that a shadowing-corrected two-scale model may be able to predict the distributed-surface portion of the sea-surface scattering from the ocean surface at grazing angles down to about 15{degree}, but at lower grazing the shadowing and large-scale curvature of the surface prevent the establishment of a Bragg resonance and invalidate the model.

  15. Thermodynamic properties of asymptotically Reissner–Nordström black holes

    SciTech Connect

    Hendi, S.H.

    2014-07-15

    Motivated by possible relation between Born–Infeld type nonlinear electrodynamics and an effective low-energy action of open string theory, asymptotically Reissner–Nordström black holes whose electric field is described by a nonlinear electrodynamics (NLED) are studied. We take into account a four dimensional topological static black hole ansatz and solve the field equations, exactly, in terms of the NLED as a matter field. The main goal of this paper is investigation of thermodynamic properties of the obtained black holes. Moreover, we calculate the heat capacity and find that the nonlinearity affects the minimum size of stable black holes. We also use Legendre-invariant metric proposed by Quevedo to obtain scalar curvature divergences. We find that the singularities of the Ricci scalar in Geometrothermodynamics (GTD) method take place at the Davies points. -- Highlights: •We examine the thermodynamical properties of black holes in Einstein gravity with nonlinear electrodynamics. •We investigate thermodynamic stability and discuss about the size of stable black holes. •We obtain analytical solutions of higher dimensional theory.

  16. The highly conserved domain of unknown function 1792 has a distinct glycosyltransferase fold

    PubMed Central

    Zhang, Hua; Zhu, Fan; Yang, Tiandi; Ding, Lei; Zhou, Meixian; Li, Jingzhi; Haslam, Stuart M; Dell, Anne; Erlandsen, Heidi; Wu, Hui

    2014-01-01

    More than 33,000 glycosyltransferases have been identified. Structural studies, however, have only revealed two distinct glycosyltransferase (GT) folds, GT-A and GT-B. Here we report a 1.34 Å resolution X-ray crystallographic structure of a previously uncharacterized “domain of unknown function” 1792 (DUF1792) and show that the domain adopts a new fold and is required for glycosylation of a family of serine-rich repeat streptococcal adhesins. Biochemical studies reveal that the domain is a glucosyltransferase, and it catalyzes the transfer of glucose to the branch point of the hexasaccharide O-linked to the serine-rich repeat of the bacterial adhesin, Fap1 of Streptococcus parasanguinis. DUF1792 homologs from both Gram-positive and Gram-negative bacteria also exhibit the activity. Thus DUF1792 represents a new family of glycosyltransferases, so we designate it as a GT-D glycosyltransferase fold. As the domain is highly conserved in bacteria and not found in eukaryotes, it can be explored as a new antibacterial target. PMID:25023666

  17. A small-molecule antivirulence agent for treating Clostridium difficile infection.

    PubMed

    Bender, Kristina Oresic; Garland, Megan; Ferreyra, Jessica A; Hryckowian, Andrew J; Child, Matthew A; Puri, Aaron W; Solow-Cordero, David E; Higginbottom, Steven K; Segal, Ehud; Banaei, Niaz; Shen, Aimee; Sonnenburg, Justin L; Bogyo, Matthew

    2015-09-23

    Clostridium difficile infection (CDI) is a worldwide health threat that is typically triggered by the use of broad-spectrum antibiotics, which disrupt the natural gut microbiota and allow this Gram-positive anaerobic pathogen to thrive. The increased incidence and severity of disease coupled with decreased response, high recurrence rates, and emergence of multiple antibiotic-resistant strains have created an urgent need for new therapies. We describe pharmacological targeting of the cysteine protease domain (CPD) within the C. difficile major virulence factor toxin B (TcdB). Through a targeted screen with an activity-based probe for this protease domain, we identified a number of potent CPD inhibitors, including one bioactive compound, ebselen, which is currently in human clinical trials for a clinically unrelated indication. This drug showed activity against both major virulence factors, TcdA and TcdB, in biochemical and cell-based studies. Treatment in a mouse model of CDI that closely resembles the human infection confirmed a therapeutic benefit in the form of reduced disease pathology in host tissues that correlated with inhibition of the release of the toxic glucosyltransferase domain (GTD). Our results show that this non-antibiotic drug can modulate the pathology of disease and therefore could potentially be developed as a therapeutic for the treatment of CDI. PMID:26400909

  18. Numerical comparison of acoustic wedge models, with application to ultrasonic telemetry.

    PubMed

    Lü, B; Darmon, M; Fradkin, L; Potel, C

    2016-02-01

    Ultrasonic telemetry imaging systems are used to monitor such immersed structures as main vessels of nuclear reactors. The interaction between acoustic beams and targets involves scattering phenomena, mainly specular reflection and tip diffraction. In order to assist in the design of imaging systems, a simulation tool is required for the accurate modeling of such phenomena. Relevant high-frequency scattering models have been developed in electromagnetic applications, in particular, the geometrical optics (GO), Geometrical Theory of Diffraction (GTD) and its uniform corrections (UAT and UTD), Kirchhoff approximation (KA) and Physical Theory of Diffraction (PTD). Before adopting any of them for simulation of scattering of acoustic waves by edged immersed rigid bodies, it is important to realize that in acoustics the characteristic dimension to the wave length ratio is usually considerably smaller than in electromagnetics and a further study is required to identify models' advantages, disadvantages and regions of applicability. In this paper their numerical comparison is carried out. As the result, the most suitable algorithm is identified for simulating ultrasonic telemetry of immersed rigid structures. PMID:26476465

  19. Geothermal Program Review VII: proceedings. DOE Research and Development for the Geothermal Marketplace

    SciTech Connect

    Not Available

    1989-01-01

    Each year the Geothermal Technology Division of the US Department of Energy conducts an indepth review of its entire geothermal R and D program. The 2--3 day conference serves several purposes: a status report on current R and D activities, an assessment of progress and problems, a review of management issues, and a technology transfer opportunity between DOE and the US geothermal industry. This year's conference, Program Review 7, was held in San Francisco on March 21--23, 1989. As indicated by its title, ''DOE Research and Development for the Geothermal Marketplace'', Program Review 7 emphasized developing technologies, concepts, and innovations having potential for commercial application in the foreseeable future. Program Review 7 was comprised of eight sessions including an opening session and a special presentation on the ''Role of Geothermal Energy in Minimizing Global Environmental Problems.'' The five technical sessions covered GTD-sponsored R and D in the areas of hydrothermal (two sessions), hot dry rock, geopressured, and magma. Presentations were made by the relevant field researchers, and sessions were chaired by the appropriate DOE Operations Office Geothermal Program Manager. The technical papers and commentary of invited speakers contained in these Proceedings have been compiled in the order in which they were presented at Program Review 7.

  20. Thermal State-of-Charge in Solar Heat Receivers

    NASA Technical Reports Server (NTRS)

    Hall, Carsie A., Jr.; Glakpe, Emmanuel K.; Cannon, Joseph N.; Kerslake, Thomas W.

    1998-01-01

    A theoretical framework is developed to determine the so-called thermal state-of-charge (SOC) in solar heat receivers employing encapsulated phase change materials (PCMS) that undergo cyclic melting and freezing. The present problem is relevant to space solar dynamic power systems that would typically operate in low-Earth-orbit (LEO). The solar heat receiver is integrated into a closed-cycle Brayton engine that produces electric power during sunlight and eclipse periods of the orbit cycle. The concepts of available power and virtual source temperature, both on a finite-time basis, are used as the basis for determining the SOC. Analytic expressions for the available power crossing the aperture plane of the receiver, available power stored in the receiver, and available power delivered to the working fluid are derived, all of which are related to the SOC through measurable parameters. Lower and upper bounds on the SOC are proposed in order to delineate absolute limiting cases for a range of input parameters (orbital, geometric, etc.). SOC characterization is also performed in the subcooled, two-phase, and superheat regimes. Finally, a previously-developed physical and numerical model of the solar heat receiver component of NASA Lewis Research Center's Ground Test Demonstration (GTD) system is used in order to predict the SOC as a function of measurable parameters.

  1. Neutron Electric Dipole Moment and Tensor Charges from Lattice QCD.

    PubMed

    Bhattacharya, Tanmoy; Cirigliano, Vincenzo; Gupta, Rajan; Lin, Huey-Wen; Yoon, Boram

    2015-11-20

    We present lattice QCD results on the neutron tensor charges including, for the first time, a simultaneous extrapolation in the lattice spacing, volume, and light quark masses to the physical point in the continuum limit. We find that the "disconnected" contribution is smaller than the statistical error in the "connected" contribution. Our estimates in the modified minimal subtraction scheme at 2 GeV, including all systematics, are g_{T}^{d-u}=1.020(76), g_{T}^{d}=0.774(66), g_{T}^{u}=-0.233(28), and g_{T}^{s}=0.008(9). The flavor diagonal charges determine the size of the neutron electric dipole moment (EDM) induced by quark EDMs that are generated in many new scenarios of CP violation beyond the standard model. We use our results to derive model-independent bounds on the EDMs of light quarks and update the EDM phenomenology in split supersymmetry with gaugino mass unification, finding a stringent upper bound of d_{n}<4×10^{-28} e cm for the neutron EDM in this scenario.

  2. Space Shuttle Underside Astronaut Communications Performance Evaluation

    NASA Technical Reports Server (NTRS)

    Hwu, Shian U.; Dobbins, Justin A.; Loh, Yin-Chung; Kroll, Quin D.; Sham, Catherine C.

    2005-01-01

    The Space Shuttle Ultra High Frequency (UHF) communications system is planned to provide Radio Frequency (RF) coverage for astronauts working underside of the Space Shuttle Orbiter (SSO) for thermal tile inspection and repairing. This study is to assess the Space Shuttle UHF communication performance for astronauts in the shadow region without line-of-sight (LOS) to the Space Shuttle and Space Station UHF antennas. To insure the RF coverage performance at anticipated astronaut worksites, the link margin between the UHF antennas and Extravehicular Activity (EVA) Astronauts with significant vehicle structure blockage was analyzed. A series of near-field measurements were performed using the NASA/JSC Anechoic Chamber Antenna test facilities. Computational investigations were also performed using the electromagnetic modeling techniques. The computer simulation tool based on the Geometrical Theory of Diffraction (GTD) was used to compute the signal strengths. The signal strength was obtained by computing the reflected and diffracted fields along the propagation paths between the transmitting and receiving antennas. Based on the results obtained in this study, RF coverage for UHF communication links was determined for the anticipated astronaut worksite in the shadow region underneath the Space Shuttle.

  3. Numerical comparison of acoustic wedge models, with application to ultrasonic telemetry.

    PubMed

    Lü, B; Darmon, M; Fradkin, L; Potel, C

    2016-02-01

    Ultrasonic telemetry imaging systems are used to monitor such immersed structures as main vessels of nuclear reactors. The interaction between acoustic beams and targets involves scattering phenomena, mainly specular reflection and tip diffraction. In order to assist in the design of imaging systems, a simulation tool is required for the accurate modeling of such phenomena. Relevant high-frequency scattering models have been developed in electromagnetic applications, in particular, the geometrical optics (GO), Geometrical Theory of Diffraction (GTD) and its uniform corrections (UAT and UTD), Kirchhoff approximation (KA) and Physical Theory of Diffraction (PTD). Before adopting any of them for simulation of scattering of acoustic waves by edged immersed rigid bodies, it is important to realize that in acoustics the characteristic dimension to the wave length ratio is usually considerably smaller than in electromagnetics and a further study is required to identify models' advantages, disadvantages and regions of applicability. In this paper their numerical comparison is carried out. As the result, the most suitable algorithm is identified for simulating ultrasonic telemetry of immersed rigid structures.

  4. Parametric Analysis of Cyclic Phase Change and Energy Storage in Solar Heat Receivers

    NASA Technical Reports Server (NTRS)

    Hall, Carsie A., III; Glakpe, Emmanuel K.; Cannon, Joseph N.; Kerslake, Thomas W.

    1997-01-01

    A parametric study on cyclic melting and freezing of an encapsulated phase change material (PCM), integrated into a solar heat receiver, has been performed. The cyclic nature of the present melt/freeze problem is relevant to latent heat thermal energy storage (LHTES) systems used to power solar Brayton engines in microgravity environments. Specifically, a physical and numerical model of the solar heat receiver component of NASA Lewis Research Center's Ground Test Demonstration (GTD) project was developed. Multi-conjugate effects such as the convective fluid flow of a low-Prandtl-number fluid, coupled with thermal conduction in the phase change material, containment tube and working fluid conduit were accounted for in the model. A single-band thermal radiation model was also included to quantify reradiative energy exchange inside the receiver and losses through the aperture. The eutectic LiF-CaF2 was used as the phase change material (PCM) and a mixture of He/Xe was used as the working fluid coolant. A modified version of the computer code HOTTube was used to generate results in the two-phase regime. Results indicate that parametric changes in receiver gas inlet temperature and receiver heat input effects higher sensitivity to changes in receiver gas exit temperatures.

  5. Decreasing geothermal energy conversion costs with advanced materials

    SciTech Connect

    Kukacka, L.E.

    1988-03-01

    If the Geothermal Technology Division (GTD) is to meet its programmatic objectives in hydrothermal fluid production and energy conversion, it is essential that new materials of construction be available. Level III Program Objectives include (1) reducing the costs associated with lost circulation episodes by 30% by 1992, (2) reducing the costs of deep wells and directionally dried wells by 10% by 1992, (3) reducing well-cementing problems for typical hydrothermal wells by 20% by 1991, and (4) the development of a corrosion-resistant and low-fouling heat exchanger tube material costing no more than three times the cost of carbon steel tubes by 1991. The Brookhaven National Laboratory (BNL) materials program is focused on meeting these objectives. Currently, work is in progress on (1) high temperature chemical systems for lost circulation control, (2) advanced high temperature (300/sup 0/C), lightweight (approx. 1.1 g/cc), CO/sub 2/-resistant well cementing materials, (3) thermally conductive composites for heat exchanger tubing, and (4) ultra high temperature (600/sup 0/C) cements for magma wells. In addition, high temperature elastomer technology developed earlier in the program is being transferred for use in the Geothermal Drilling Organization programs on drill pipe protectors, rotating head seals, and blow-out preventors. Recent accomplishments and the current status of work in each subtask are summarized in the paper.

  6. Electromagnetic scattering from a class of open-ended waveguide discontinuities

    NASA Technical Reports Server (NTRS)

    Altintas, A.; Pathak, P. H.; Burnside, Walter D.

    1986-01-01

    A relatively simple high frequency analysis of electromagnetic scattering from a class of open-ended waveguide discontinuites was developed. The waveguides are composed of perfectly-conducting sections in which the electromagnetic field can be written as the sum of waveguide modes. Junctions are formed at the open end and also within interior regions where different sections are joined. The reflection and transmission properties of each junction are described in terms of a scattering matrix which is determined by combining the modal ray picture with high frequency techniques such as the Geometrical Theory of Diffraction (GTD), the Equivalent Current Method (ECM), and modifications of the Physical Theory of Diffraction (PTD). A new set of equivalent circuits are employed in this ECM analysis which leads to a simple treatment of many types of junction discontinuities. Also, a new procedure is presented to improve the efficiency of the aperture integration at the open end which is required in the PTD procedure for finding the fields radiated from (or coupled to) the open end. Once the scattering matrices are determined, they are then combined using a self-consistent multiple scattering method to obtain the total scattered fields.

  7. Affordable Development and Demonstration of a Small NTR engine and Stage: A Preliminary NASA, DOE, and Industry Assessment

    NASA Technical Reports Server (NTRS)

    Borowski, S. K.; Sefcik, R. J.; Fittje, J. E.; McCurdy, D. R.; Qualls, A. L.; Schnitzler, B. G; Werner, J.; Weitzberg, A.; Joyner, C. R.

    2015-01-01

    In FY'11, Nuclear Thermal Propulsion (NTP) was identified as a key propulsion option under the Advanced In-Space Propulsion (AISP) component of NASA's Exploration Technology Development and Demonstration (ETDD) program A strategy was outlined by GRC and NASA HQ that included 2 key elements -"Foundational Technology Development" followed by specific "Technology Demonstration" projects. The "Technology Demonstration "element proposed ground technology demonstration (GTD) testing in the early 2020's, followed by a flight technology demonstration (FTD) mission by approx. 2025. In order to reduce development costs, the demonstration projects would focus on developing a small, low thrust (approx. 7.5 -16.5 klb(f)) engine that utilizes a "common" fuel element design scalable to the higher thrust (approx. 25 klb(f)) engines used in NASA's Mars DRA 5.0 study(NASA-SP-2009-566). Besides reducing development costs and allowing utilization of existing, flight proven engine hard-ware (e.g., hydrogen pumps and nozzles), small, lower thrust ground and flight demonstration engines can validate the technology and offer improved capability -increased payloads and decreased transit times -valued for robotic science missions identified in NASA's Decadal Study.

  8. Geothermal Program Review VI: proceedings. Beyond goals and objectives

    SciTech Connect

    Not Available

    1988-01-01

    Program Review VI was comprised of six sessions, including an opening session, four technical sessions that addressed each of the major DOE research areas, and a session on special issues. The technical sessions were on Hydrothermal, Hot Dry Rock, Geopressured and Magma resources. Presenters in the technical sessions discussed their R and D activities within the context of specific GTD Programmatic Objectives for that technology, their progress toward achieving those objectives, and the value of those achievements to industry. The ''Special Issues'' presentations addressed several topics such as the interactions between government and industry on geothermal energy R and D; the origin and basis for the programmatic objectives analytical computer model; and international marketing opportunities for US geothermal equipment and services. The unique aspect of Program Review VI was that it was held in conjunction with the National Geothermal Association's Industry Round Table on Federal R and D. The Round Table provided a forum for open and lively discussions between industry and government researchers and gave industry an opportunity to convey their needs and perspectives on DOE's research programs. These discussions also provided valuable information to DOE regarding industry's priorities and directions.

  9. CIVA: an expertise platform for simulation and processing NDT data.

    PubMed

    Calmon, P; Mahaut, S; Chatillon, S; Raillon, R

    2006-12-22

    Ultrasonic modeling and simulation are more and more widely used by the different actors of industrial NDT. The applications are numerous and show a great variety: help for diagnosis, data reconstruction, performance demonstration, probe design and inspection parameters settling, virtual testing etc. The CEA (the French Atomic Energy Commission) is strongly involved in this evolution with the development of the CIVA expertise platform which gathers in the same software advanced processing and modeling tools. In the aim of fulfilling requirements of an intensive use the choice has been made to mainly adopt semi-analytical approximated methods. The wave propagation modeling is based on an integral formulation of the radiated field and applies the so-called pencil method. The modeling of beam-defect interaction and echoes formation mechanisms apply approximated theories such as Kirchhoff approximation or GTD. Over the years and with successive versions of the software, this approach is enriched by adaptations and improvements of the existing models or by new models, in order to extend the field of applicability of the simulation.

  10. Numerical methods for analyzing electromagnetic scattering

    NASA Technical Reports Server (NTRS)

    Lee, S. W.; Lo, Y. T.; Chuang, S. L.; Lee, C. S.

    1985-01-01

    Attenuation properties of the normal modes in an overmoded waveguide coated with a lossy material were analyzed. It is found that the low-order modes, can be significantly attenuated even with a thin layer of coating if the coating material is not too lossy. A thinner layer of coating is required for large attenuation of the low-order modes if the coating material is magnetic rather than dielectric. The Radar Cross Section (RCS) from an uncoated circular guide terminated by a perfect electric conductor was calculated and compared with available experimental data. It is confirmed that the interior irradiation contributes to the RCS. The equivalent-current method based on the geometrical theory of diffraction (GTD) was chosen for the calculation of the contribution from the rim diffraction. The RCS reduction from a coated circular guide terminated by a PEC are planned schemes for the experiments are included. The waveguide coated with a lossy magnetic material is suggested as a substitute for the corrugated waveguide.

  11. Imaging and Clinical Data of Placental Site Trophoblastic Tumor: A Case Report

    PubMed Central

    Niknejadi, Maryam; Ahmadi, Firoozeh; Akhbari, Farnaz

    2016-01-01

    Placental site trophoblastic tumor (PSTT) is a very rare variant of gestational trophoblastic tumor. It can occur after normal termination of pregnancy or spontaneous abortion and ectopic or molar pregnancy. There is a wide range of clinical manifestations from a benign condition to an aggressive disease with fatal outcome. One of the most important characteristics of PSTT, unlike other forms of gestational trophoblastic diseases (GTD) is the presence of low beta-subunit of human chorionic gonadotropin (β-hCG) levels because it is a neoplastic proliferation of intermediate trophoblastic cells. However, human placental lactogen (hPL) is increased on histologic section and in the serum of patients too. We present a case of PSTT and discuss the differential diagnosis in order to further familiarize physicians with the diagnosis and treatment of this disease. It has a varied clinical spectrum and usually presents with irregular vaginal bleeding or amenorrhea. Diagnosis is confirmed by dilatation and curettage (D and C) and hysterectomy. Because chemotherapy is not effective, surgery is the cornerstone of treatment. This case is presented because it is a rare neoplasm with different treatments and it should be differentiated from molar pregnancy.

  12. Imaging and Clinical Data of Placental Site Trophoblastic Tumor: A Case Report.

    PubMed

    Niknejadi, Maryam; Ahmadi, Firoozeh; Akhbari, Farnaz

    2016-04-01

    Placental site trophoblastic tumor (PSTT) is a very rare variant of gestational trophoblastic tumor. It can occur after normal termination of pregnancy or spontaneous abortion and ectopic or molar pregnancy. There is a wide range of clinical manifestations from a benign condition to an aggressive disease with fatal outcome. One of the most important characteristics of PSTT, unlike other forms of gestational trophoblastic diseases (GTD) is the presence of low beta-subunit of human chorionic gonadotropin (β-hCG) levels because it is a neoplastic proliferation of intermediate trophoblastic cells. However, human placental lactogen (hPL) is increased on histologic section and in the serum of patients too. We present a case of PSTT and discuss the differential diagnosis in order to further familiarize physicians with the diagnosis and treatment of this disease. It has a varied clinical spectrum and usually presents with irregular vaginal bleeding or amenorrhea. Diagnosis is confirmed by dilatation and curettage (D and C) and hysterectomy. Because chemotherapy is not effective, surgery is the cornerstone of treatment. This case is presented because it is a rare neoplasm with different treatments and it should be differentiated from molar pregnancy. PMID:27679689

  13. Edge diffracted caustic fields. [spacecraft antenna radiation patterns

    NASA Technical Reports Server (NTRS)

    Burnside, W. D.; Peters, L., Jr.

    1974-01-01

    The fields near a caustic created by an edge diffraction process are computed using the equivalent current concept. These fields are shown to have the property commonly associated with ray optical analysis or the Geometrical Theory of Diffraction (GTD), e.g., a 90 deg phase shift as the ray passes through the caustic. The present effort is directed toward consideration of the caustic created by an edge diffraction process. Particular attention is focused on electromagnetic excitation. The acoustic excitation for the hard boundary condition is outlined in an appendix. In addition, goal is to establish the extent of the caustic region. This is of particular importance when a ray optical solution involves multiply-diffracted terms in that the minimum size of the body that can be analyzed may be restricted by the extent of the caustic, i.e., the 90 deg phase shift used in ray optical analysis may be introduced only if the caustic is contained on the surface being studied.

  14. L'astronomie des Anciens

    NASA Astrophysics Data System (ADS)

    Nazé, Yaël

    2009-04-01

    Quelle que soit la civilisation à laquelle il appartient, l'être humain cherche dans le ciel des réponses aux questions qu'il se pose sur son origine, son avenir et sa finalité. Le premier mérite de ce livre est de nous rappeler que l'astronomie a commencé ainsi à travers les mythes célestes imaginés par les Anciens pour expliquer l'ordre du monde et la place qu'ils y occupaient. Mais les savoirs astronomiques passés étaient loin d'être négligeables et certainement pas limités aux seuls travaux des Grecs : c'est ce que l'auteur montre à travers une passionnante enquête, de Stonehenge à Gizeh en passant par Pékin et Mexico, fondée sur l'étude des monuments anciens et des sources écrites encore accessibles. Les tablettes mésopotamiennes, les annales chinoises, les chroniques médiévales, etc. sont en outre d'une singulière utilité pour les astronomes modernes : comment sinon remonter aux variations de la durée du jour au cours des siècles, ou percer la nature de l'explosion qui a frappé tant d'observateurs en 1054 ? Ce livre offre un voyage magnifiquement illustré à travers les âges, entre astronomie et archéologie.

  15. Contribution à la modélisation du soudage TIG des tôles minces d'acier austénitique 304L par un modèle source bi-elliptique, avec confrontation expérimentale

    NASA Astrophysics Data System (ADS)

    Aissani, M.; Maza, H.; Belkessa, B.; Maamache, B.

    2005-05-01

    Ce travail contribue dans la modélisation du phénomène du soudage de l'acier inoxydable Austénitique 304L, afin d'étudier le comportement thermique d'un joint de soudure, obtenu par le procédé de soudage à l'arc électrique TIG (Tungsten-Inert-Gas). Le modèle simulant la source d'énergie de soudage, utilise une distribution surfacique Gaussienne du flux de chaleur provenant de l'arc électrique. La forme de cette source est supposée circulaire pour un premier cas et de forme bi-elliptique pour un second cas, tout en procédant à l'évaluation des champs et cycles thermiques à chaque instant, pour déterminer l'étendu des zones à risque, et l'effet de la vitesse de soudage sur ces dernières. Permettant ainsi de remonter par la suite, aux problèmes de contraintes résiduelles et déformations générées dans l'assemblage soudé. L'équation de chaleur régissant le problème est discrétisée par la méthode des volumes finis. Les calculs sont effectués en considérant que les propriétés physiques et thermiques ainsi que les conditions aux limites de convection et rayonnement, sont dépendante de la température. Pour évaluer la précision du modèle, une comparaison avec des mesures expérimentales de température d'un essai de soudage a été effectuée, les résultats indiquent un bon accord.

  16. Fresnel zone and reflectarray antennas for space missions: Concepts, computational techniques and characterizations

    NASA Astrophysics Data System (ADS)

    Khayatian, Behrouz

    Reflector antennas generally employ parabolic shaped main reflectors and have found a wide range of applications for both earth stations and satellite systems. Increasingly, one may find many advantages in minimizing antenna shaping requirement and weight as well as more compact designs by employing flat reflectors (either on the main reflector or on the subreflector) which can achieve a desired set of criteria for antenna performance. Two electrically large antennas which use flat min reflectors are Fresnel Zone (FZ) and reflectarray antennas which are being addressed in this dissertation. Analytical techniques are proposed, implemented, and verified to analyze these reflector geometries. A two dimensional (2-D) multi-scatterer analysis is formulated and implemented using various electromagnetic scattering techniques such as Physical Optics (PO), Method of Moments (MoM), and Geometrical Theory of Diffraction (GTD). The capability of the 2-D technique is further extended for dual reflector analysis with flat subreflector panels as well as design and analysis of FZ antennas with a proposed space missions application in solar sailing. FZ antenna design is based on establishing regions of quasi-uniform phases according to the PO current on the reflector face. The concepts extracted from the 2-D analysis of FZ reflectors is carried to the three dimensional (3-D) cases and incorporated into a multi reflector code, which has been widely used in variety of reflector applications. Like FZ antennas, reflectarrays work according to a similar set of principals by achieving a uniform phase current on the flat reflectarray surface. Accordingly, an analytical methodology is proposed and implemented within the structure of the multi-reflector code to analyze and give design criteria for both single and dual reflectarray configurations. This technique is compared to measured results published for single reflectarrays and is investigated for near-field Gregorian reflectarrays with

  17. RF Exposure Analysis for Multiple Wi-Fi Devices In Enclosed Environment

    NASA Technical Reports Server (NTRS)

    Hwu, Shian U.; Rhodes, Bryan A.; deSilva, B. Kanishka; Sham, Catherine C.; Keiser, James R.

    2013-01-01

    Wi-Fi devices operated inside a metallic enclosure have been investigation in the recent years. A motivation for this study is to investigate wave propagation inside an enclosed environment such as elevator, car, aircraft, and spacecraft. There are performances and safety concerned that when the RF transmitters are used in the metallic enclosed environments. In this paper, the field distributions inside a confined room were investigated with multiple portable Wi-Fi devices. Computer simulations were performed using the rigorous computational electromagnetics (CEM). The method of moments (MoM) was used to model the mutual coupling among antennas. The geometrical theory of diffraction (GTD) was applied for the multiple reflections off the ground and walls. The prediction of the field distribution inside such environment is useful for the planning and deployment of a wireless radio and sensor system. Factors that affect the field strengths and distributions of radio waves in confined space were analyzed. The results could be used to evaluate the RF exposure safety in confined environment. By comparing the field distributions for various scenarios, it was observed that the Wi-Fi device counts, spacing and relative locations in the room are important factors in such environments. The RF Keep Out Zone (KOZ), where the electric field strengths exceed the permissible RF exposure limit, could be used to assess the RF human exposure compliance. As shown in this study, it s possible to maximize or minimize field intensity in specific area by arranging the Wi-Fi devices as a function of the relative location and spacing in a calculated manner.

  18. A line-of-sight propagation model for calculating atmospheric, sea, terrain multipath, and clutter at microwave frequencies

    NASA Astrophysics Data System (ADS)

    Ott, Randolph H.

    1997-03-01

    The two-dimensional parabolic wave equation (PE) is solved asymptotically in order to derive a propagation/scattering model for propagation in a stratified atmosphere, together with scattering and diffraction from the sea/terrain surface, within line of sight. The asymptotic solution to the PE begins by expanding the unknown field in a Luneberg-Kline expansion. The first-order solution to the Luneberg-Kline expansion yields the eikonal equation for the ray trajectory, and the second-order solution yields the transport equation for the energy density of the rays along the trajectory. The solution to the eikonal and transport equations is used to derive an asymptotic result for the plane wave spectrum solution for the PE, referred to as the wave-theoretic model. The asymptotic solution for the field shows the relationship between a properly directed tube of rays in the atmosphere satisfying the eikonal and conservation of energy equations and the same tube of rays striking an edge and being diffracted, as in the geometrical theory of diffraction (GTD). The solution for the eikonal yields the ray trajectory in the stratified atmosphere and therefore the grazing angle on the sea/terrain profile necessary for calculating multipath and clutter. Also, a new derivation for the backscatter from a deterministic sea/terrain profile is given which agrees with Collin's [1992] new full wave theory and at grazing reduces to the perturbation result with the correct polarization dependence. Incorporating the various electromagnetic propagation/scattering mechanisms in one model yields a prediction tool that can be applied to a large class of propagation/scattering problems such as the analysis of radar performance in a littoral scenario, or the performance of a line-of-sight communication link operating over irregular terrain.

  19. On the Importance of the Distance Measures Used to Train and Test Knowledge-Based Potentials for Proteins

    PubMed Central

    Carlsen, Martin; Koehl, Patrice; Røgen, Peter

    2014-01-01

    Knowledge-based potentials are energy functions derived from the analysis of databases of protein structures and sequences. They can be divided into two classes. Potentials from the first class are based on a direct conversion of the distributions of some geometric properties observed in native protein structures into energy values, while potentials from the second class are trained to mimic quantitatively the geometric differences between incorrectly folded models and native structures. In this paper, we focus on the relationship between energy and geometry when training the second class of knowledge-based potentials. We assume that the difference in energy between a decoy structure and the corresponding native structure is linearly related to the distance between the two structures. We trained two distance-based knowledge-based potentials accordingly, one based on all inter-residue distances (PPD), while the other had the set of all distances filtered to reflect consistency in an ensemble of decoys (PPE). We tested four types of metric to characterize the distance between the decoy and the native structure, two based on extrinsic geometry (RMSD and GTD-TS*), and two based on intrinsic geometry (Q* and MT). The corresponding eight potentials were tested on a large collection of decoy sets. We found that it is usually better to train a potential using an intrinsic distance measure. We also found that PPE outperforms PPD, emphasizing the benefits of capturing consistent information in an ensemble. The relevance of these results for the design of knowledge-based potentials is discussed. PMID:25411785

  20. The Pliocene Yafo Formation in Israel: Hydrogeologically inert or active?

    NASA Astrophysics Data System (ADS)

    Avisar, D.; Rosenthal, E.; Shulman, H.; Zilberbrand, M.; Flexer, A.; Kronfeld, J.; Ben Avraham, Z.; Fleischer, L.

    mur de l'aquifère côtier (série de Kurkar) d'Israël, ont été considérées comme un ensemble extrêmement épais, sans déformation tectonique et totalement imperméable. À la suite de l'exploitation intensive de l'eau souterraine de l'aquifère sus-jacent de la série de Kurkar, des eaux salées et des saumures sont rencontrées occasionnellement dans les parties les plus profondes de cet aquifère et toujours au contact de l'imperméable sous-jacent de la formation de Yafo. Cette étude a révélé que cet imperméable n'est pas une unité géologique uniforme et imperméable, mais qu'il s'agit plutôt d'une alternance de couches perméables et imperméables dans la formation de Yafo contenant des fluides sous des pressions fortes avec des salinités différentes (?) et en général élevées (?). Les niveaux perméables sont en discordance angulaire et en contact direct avec l'aquifère sus-jacent de la série de Kurkar. La formation de Yafo et les unités géologiques situées dessous et dessus sont disloquées par de nombreuses systèmes de failles, qui facilitent le passage des saumures dans l'aquifère de la série de Kurkar. La mobilisation des fluides salins et leur injection dans l'aquifère de Kurkar pourraient être dues soit à la diffusion des fluides salins dans les horizons perméables du Petah Tiqva au travers des argiles de la formation de Yafo, soit leur remontée par upconing sous l'effet de pompages intensifs dans l'aquifère de la plaine côtière. Il peut aussi être causé par la remontée des eaux salines selon le pendage sous l'effet d'une surpression provoquée par une accumulation considérable de gaz dans les horizons imperméables. Un autre mécanisme possible pourrait être un contact hydraulique avec des saumures sous pression, remontant le long des zones de faille depuis des réservoirs profonds jurassiques ou crétacés. L'expulsion d'eau saline interstitielle des argiles de la formation de Yafo dans l'aquifère de Kurkar est d

  1. Heat focussing, granite genesis and inverted metamorphic gradients in continental collision zones

    NASA Astrophysics Data System (ADS)

    Jaupart, Claude; Provost, Ariel

    1985-05-01

    The thermal conductivity of sedimentary rocks is usually much lower than that of crystalline rocks, gneisses and granites. Continental collision zones are characterized by large-scale thrusts which superpose crystalline basement and sedimentary layers. This leads to heat refraction effects of significant magnitude. Sedimentary layers act as a barrier to the transport of heat. We show that the peculiar geometry of a gently sloping sedimentary layer thrust into more conductive rocks is very efficient in diverting the vertical flux of heat. Temperatures can vary by more than 50% along the horizontal and reach a marked maximum at the top of crystalline layers. These results are in general agreement with the main features of orogenic belts as exemplified by the Himalayas. They explain why the young leucogranites of the Main Central Thrust (MCT) are confined to a narrow belt at the top of the basement slab. They also account for the inverted metamorphic gradient observed there. In a crustal accretionary wedge, folding and thrusting modify the structure of the upper crust, by thickening the sedimentary cover and by introducing sedimentary rocks at depth. This leads to high temperatures at shallow depths in specific places. Les zones de collision continentale se caractérisent par de grands chevauchementsàfaible pendage qui empilent les unes sur les autres des couches de socle cristallin et des couches sédimentaires. Cette structure particulière engendre d'importants effets de réfraction thermique. En effet, leur conductibilitéthermiqueétant normalement bien plus faible que celle des roches cristallines, les formations sédimentaires font office de barrières pour le transfert thermique: le flux de chaleur se trouve fortement dévié. Dans un plan horizontal, la température peut varier de plus de 50%, les maximaétant situésàl'interface supérieur des dalles cristallines. En ces endroits précis, les isothermes profonds remontent très significativement. Ces r

  2. Les garrots de prélèvement, un drame chez le nourrisson: à propos de 3 cas

    PubMed Central

    Ouangré, Edgar; Bazongo, Moussa; Ouédraogo, Isso; Zida, Maurice; Ouedraogo, Daouda; Sanou, Adama; Bonkoungou, Gilbert Patindé; Doamba, Rodrigue Namékinsba; Zongo, Nayi; Traore, Si Simon

    2016-01-01

    Le délai pour la levée d'un garrot sur un membre est limité, tout retard, surtout après la 3ème heure expose à un risque d'amputation de celui-ci. Notre objectif a été de rapporter trois cas de gangrène ischémique de membre par oubli d'un garrot après un prélèvement sanguin, afin d'interpeler le personnel soignant sur ses dangers. Il s'est agi de trois nourrissons dont deux de 3 mois et un de 5 mois, reçus aux urgences viscérales du CHU-Yalgado Ouédraogo pour tuméfaction du membre thoracique gauche. Dans leurs antécédents, on a noté une pose de garrot pour prélèvement de sang qui a été oublié pendant 24 heures dans deux cas et 48 heures dans un cas. L'examen avait retrouvé un œdème diffus associé à un sphacèle du membre supérieur remontant jusqu'au 1/3 moyen du bras; une abolition des pouls ulnaire et radial ainsi que de la sensibilité de la main dans 2 cas. Dans un cas les signes étaient atténués. Le diagnostic de gangrène ischémique de membre a été retenu dans tous les cas. La biologie réalisée était normale. En urgence, il a été réalisé une amputation trans-humérale dans 2 cas et un débridement associé à une amputation de quatre doigts dans un cas. L’évolution a été simple dans tous les cas. La gangrène sèche iatrogène de membre par garrot en milieu hospitalier ne devrait pas se concevoir. Cela passe par la rigueur dans l'administration des soins et une surveillance régulière et attentive des patients. PMID:27217892

  3. Diagnostiquer l’hypertension artérielle

    PubMed Central

    Gelfer, Mark; Dawes, Martin; Kaczorowski, Janusz; Padwal, Raj; Cloutier, Lyne

    2015-01-01

    Résumé Objectif Mettre en lumière les recommandations 2015 du Programme éducatif canadien sur l’hypertension (PECH) sur le diagnostic et l’évaluation de l’hypertension artérielle (HTA). Qualité des données Une recherche systématique remontant à août 2014 a été effectuée par un bibliothécaire de la Collaboration Cochrane dans les banques de données MEDLINE et PubMed. Les résultats de la recherche ont fait l’objet d’une évaluation critique par le sous-comité du PECH sur la mesure de la pression artérielle (PA) et le diagnostic d’HTA, et les recommandations fondées sur les données probantes ont été soumises au Comité central d’examen du PECH aux fins d’examen indépendant et de classement. Finalement, les résultats et recommandations ont été présentés au Groupe de travail sur les recommandations aux fins de discussion, de débat, d’approbation et de vote. Les principales recommandations reposent sur des données probantes de niveau II. Message principal Selon les données probantes les plus récentes, le PECH a formulé 4 nouvelles recommandations classées dans 2 vastes catégories pour améliorer la mesure de la PA et la façon dont l’HTA est diagnostiquée en 2015. Il est fortement recommandé de mesurer la PA à l’aide d’appareils électroniques en clinique plutôt que par auscultation. Chez les patients dont les mesures en clinique sont élevées, le PECH recommande de se tourner précocement vers les mesures ambulatoires, préférablement le monitorage ambulatoire de la PA, afin d’identifier rapidement les patients atteints du syndrome du sarrau blanc. Conclusion Il est crucial d’améliorer la justesse diagnostique afin d’optimiser la prise en charge de l’HTA au Canada. Les mises à jour annuelles du PECH veillent à ce que les praticiens disposent de renseignements fondés sur les données probantes à jour pour éclairer leur pratique.

  4. Mapping Isoflavone QTL with Main, Epistatic and QTL × Environment Effects in Recombinant Inbred Lines of Soybean

    PubMed Central

    Wang, Yan; Han, Yingpeng; Zhao, Xue; Li, Yongguang; Teng, Weili; Li, Dongmei; Zhan, Yong; Li, Wenbin

    2015-01-01

    Soybean (Glycine max (L.) Merr.) isoflavone is important for human health and plant defense system. To identify novel quantitative trait loci (QTL) and epistatic QTL underlying isoflavone content in soybean, F5:6, F5:7 and F5:8 populations of 130 recombinant inbred (RI) lines, derived from the cross of soybean cultivar ‘Zhong Dou 27′ (high isoflavone) and ‘Jiu Nong 20′ (low isoflavone), were analyzed with 95 new SSR markers. A new linkage map including 194 SSR markers and covering 2,312 cM with mean distance of about 12 cM between markers was constructed. Thirty four QTL for both individual and total seed isoflavone contents of soybean were identified. Six, seven, ten and eleven QTL were associated with daidzein (DZ), glycitein (GC), genistein (GT) and total isoflavone (TI), respectively. Of them 23 QTL were newly identified. The qTIF_1 between Satt423 and Satt569 shared the same marker Satt569 with qDZF_2, qGTF_1 and qTIF_2. The qGTD2_1 between Satt186 and Satt226 was detected in four environments and explained 3.41%-10.98% of the phenotypic variation. The qGTA2_1, overlapped with qGCA2_1 and detected in four environments, was close to the previously identified major QTL for GT, which were responsible for large a effects. QTL (qDZF_2, qGTF_1 and qTIF_2) between Satt144-Satt569 were either clustered or pleiotropic. The qGCM_1, qGTM_1 and qTIM_1 between Satt540-Sat_244 explained 2.02%–9.12% of the phenotypic variation over six environments. Moreover, the qGCE_1 overlapped with qGTE_1 and qTIE_1, the qTIH_2 overlapped with qGTH_1, qGCI_1 overlapped with qDZI_1, qTIL_1 overlapped with qGTL_1, and qTIO_1 overlapped with qGTO_1. In this study, some of unstable QTL were detected in different environments, which were due to weak expression of QTL, QTL by environment interaction in the opposite direction to a effects, and/or epistasis. The markers identified in multi-environments in this study could be applied in the selection of soybean cultivars for higher

  5. Numerical Simulation of Transport Phenomena for a Double-Layer Laser Powder Deposition of Single-Crystal Superalloy

    NASA Astrophysics Data System (ADS)

    Liu, Zhaoyang; Qi, Huan

    2014-04-01

    A turbine blade made of single-crystal superalloys has been commonly used in gas turbine and aero engines. As an effective repair technology, laser powder deposition has been implemented to restore the worn turbine blade tips with a near-net shape capability and highly controllable solidified microstructure. Successful blade repair technology for single-crystal alloys requires a continuous epitaxial grain growth in the same direction of the crystalline orientation of the substrate material to the newly deposited layers. This work presents a three-dimensional numerical model to simulate the transport phenomena for a multilayer coaxial laser powder deposition process. Nickel-based single-crystal superalloy Rene N5 powder is deposited on a directional solidified substrate made of nickel-based directional-solidified alloy GTD 111 to verify the simulation results. The effects of processing parameters including laser power, scanning speed, and powder feeding rate on the resultant temperature field, fluid velocity field, molten pool geometric sizes, and the successive layer remelting ratios are studied. Numerical simulation results show that the maximum temperature of molten pool increases over layers due to the reduced heat dissipation capacity of the deposited geometry, which results in an increased molten pool size and fluid flow velocity at the successive deposited layer. The deposited bead geometry agrees well between the simulation and the experimental results. A large part of the first deposition layer, up to 85 pct of bead height, can be remelted during the deposition of the second layer. The increase of scanning speed decreases the ratio of G/ V (temperature gradient/solidification velocity), leading to an increased height ratio of the misoriented grain near the top surface of the previous deposited layer. It is shown that the processing parameters used in the simulation and experiment can produce a remelting ratio R larger than the misoriented grain height ratio

  6. Influence versus intent for predictive analytics in situation awareness

    NASA Astrophysics Data System (ADS)

    Cui, Biru; Yang, Shanchieh J.; Kadar, Ivan

    2013-05-01

    Database (GTD). Our results reveals the benefits to perform joint predictive analytics with both attitude and influence. At the same time, we discover significant challenges in deriving influence and attitude from indirect observables for diverse adversarial behavior. These observations warrant further investigation of optimal use of influence and attitude for predictive analytics, as well as the potential inclusion of other environmental or capability elements for the actors.

  7. Effects of Ambient High Temperature Exposure on Alumina-Titania High Emittance Surfaces for Solar Dynamic Systems

    NASA Technical Reports Server (NTRS)

    deGroh, Kim K.; Smith, Daniela C.; Wheeler, Donald R.; MacLachlam, Brian J.

    1998-01-01

    Solar dynamic (SD) space power systems require durable, high emittance surfaces on a number of critical components, such as heat receiver interior surfaces and parasitic load radiator (PLR) elements. To enhance surface characteristics, an alumina-titania coating has been applied to 500 heat receiver thermal energy containment canisters and the PLR of NASA Lewis Research Center's (LeRC) 2 kW SD ground test demonstrator (GTD). The alumina-titania coating was chosen because it had been found to maintain its high emittance under vacuum (less than or equal to 10(exp -6) torr) at high temperatures (1457 F (827 C)) for an extended period (approximately 2,700 hours). However, preflight verification of SD systems components, such as the PLR require operation at ambient pressure and high temperatures. Therefore, the purpose of this research was to evaluate the durability of the alumina-titania coating at high temperature in air. Fifteen of sixteen alumina-titania coated Incoloy samples were exposed to high temperatures (600 F (316 C) to l500 F (816 C)) for various durations (2 to 32 hours). Samples, were characterized prior to and after heat treatment for reflectance, solar absorptance, room temperature emittance and emittance at 1,200 F (649 C). Samples were also examined to detect physical defects and to determine surface chemistry using optical microscopy, scanning electron microscopy operated with an energy dispersive spectroscopy (EDS) system, and x ray photoelectron spectroscopy (XPS). Visual examination of the heat-treated samples showed a whitening of samples exposed to temperatures of 1,000 F (538 C) and above. Correspondingly, the optical properties of these samples had degraded. A sample exposed to 1,500 F (816 C) for 24 hours had whitened and the thermal emittance at 1,200 F (649 C) had decreased from the non-heat treated value of 0.94 to 0.62. The coating on this sample had become embrittled with spalling off the substrate noticeable at several locations. Based

  8. Electromagnetic sensing for the monitoring of structures and infrastructures: a model for the diffraction by penetrable wedges

    NASA Astrophysics Data System (ADS)

    Riccio, G.; Gennarelli, G.

    2012-04-01

    As well-known, the observation of structures and infrastructures by radar remote sensing involves the investigation of the high-frequency electromagnetic scattering by canonical shapes, such as cylinders and wedges. For instance, the ruptures caused by natural disasters can be represented in the form of a wedge-shaped fracture [1]. They modify the electromagnetic response of the scene under investigation and the Geometrical Theory of Diffraction (GTD) can be used as efficient tool for describing this occurrence. Diffraction by a wedge is a well-covered topic in the scientific literature, but the available results mainly concern impenetrable structures. The aim of this work is to provide Uniform Asymptotic Physical Optics (UAPO) diffraction coefficients in the case of lossless penetrable wedges illuminated by plane waves having normal incidence with respect to the edge. To this end, the original problem is subdivided into two parts relevant to the internal region of the wedge and the surrounding space. For what concerns the evaluation of the field diffracted in the outer region, equivalent electric and magnetic PO surface currents are used as sources in the radiation integral. They lie on the external faces of the wedge and their expressions change in accordance with the incidence direction. As a matter of fact, they involve the reflection and transmission Fresnel's coefficients when one external face is directly illuminated, and only the reflection Fresnel's coefficients if both the external faces are considered. A useful approximation and a uniform asymptotic evaluation of the resulting radiation integrals allow one to obtain the diffraction coefficients in terms of the Geometrical Optics (GO) response and the standard transition function of the Uniform Theory of Diffraction (UTD) [2]. The evaluation of the field diffracted in the inner region is tackled and solved by using equivalent PO surface currents on the internal faces of the wedge. Once such currents are

  9. Molecular Basis of the Waxy Endosperm Starch Phenotype in Broomcorn Millet (Panicum miliaceum L.)

    PubMed Central

    Hunt, Harriet V.; Denyer, Kay; Packman, Len C.; Jones, Martin K.; Howe, Christopher J.

    2010-01-01

    Waxy varieties of the tetraploid cereal broomcorn millet (Panicum miliaceum L.) have endosperm starch granules lacking detectable amylose. This study investigated the basis of this phenotype using molecular and biochemical methods. Iodine staining of starch granules in 72 plants from 38 landrace accessions found 58 nonwaxy and 14 waxy phenotype plants. All waxy types were in plants from Chinese and Korean accessions, a distribution similar to that of the waxy phenotype in other cereals. Granule-bound starch synthase I (GBSSI) protein was present in the endosperm of both nonwaxy and waxy individuals, but waxy types had little or no granule-bound starch synthase activity compared with the wild types. Sequencing of the GBSSI (Waxy) gene showed that this gene is present in two different forms (L and S) in P. miliaceum, which probably represent homeologues derived from two distinct diploid ancestors. Protein products of both these forms are present in starch granules. We identified three polymorphisms in the exon sequence coding for mature GBSSI peptides. A 15-bp deletion has occurred in the S type GBSSI, resulting in the loss of five amino acids from glucosyl transferase domain 1 (GTD1). The second GBSSI type (L) shows two sequence polymorphisms. One is the insertion of an adenine residue that causes a reading frameshift, and the second causes a cysteine–tyrosine amino acid polymorphism. These mutations appear to have occurred in parallel from the ancestral allele, resulting in three GBSSI-L alleles in total. Five of the six possible genotype combinations of the S and L alleles were observed. The deletion in the GBSSI-S gene causes loss of protein activity, and there was 100% correspondence between this deletion and the waxy phenotype. The frameshift mutation in the L gene results in the loss of L-type protein from starch granules. The L isoform with the tyrosine residue is present in starch granules but is nonfunctional. This loss of function may result from the

  10. Groundwater and climate change: a sensitivity analysis for the Grand Forks aquifer, southern British Columbia, Canada

    NASA Astrophysics Data System (ADS)

    Allen, D. M.; Mackie, D. C.; Wei, M.

    rivières Kettle et Granby, qui coulent dans la vallée. Toutes les simulations ont montré des différences relativement faibles dans la configuration d'ensemble de la nappe et dans la direction générale des écoulements. Des simulations de conditions de recharge forte et de recharge faible produisent respectivement une remontée de 0,05 m et un abaissement de 0,025 m, approximativement, des cotes de la nappe pour l'ensemble de l'aquifère. Des changements simulés de la cote du niveau de la rivière, pour refléter des niveaux plus hauts que ceux des pics de crues (de 20 et de 50%), produisent respectivement des remontées de la nappe de 2,72 et 3,45 m en moyenne. Des changements simulés de l'altitude du niveau de la rivière, pour refléter des niveaux plus bas que ceux de basses eaux (de 20 et de 50%), produisent respectivement des abaissements de la nappe de 0,48 et 2,10 m en moyenne. Les altitudes courantes observées de la nappe dans la vallée sont cohérentes avec une cote moyenne du niveau de la rivière (entre les niveaux courants de basses eaux et de crues). El acuífero de los Grand Forks, situado al sur de la Columbia Británica central (Canadá) ha sido utilizado como lugar de estudio para modelar la sensibilidad de un acuífero a los cambios en la recarga y el caudal de los ríos de acuerdo con escenarios previstos de cambio climático en la región. Los resultados sugieren que las variaciones en la recarga al acuífero bajo los diversos escenarios, que han sido modelados en régimen estacionario, tienen un impacto mucho menor en las aguas subterráneas que los cambios en el caudal de los ríos Kettle y Granby, que discurren por el valle. Todas las simulaciones muestran diferencias relativamente pequeñas en la configuración regional de los niveles freáticos y en la dirección general del flujo subterráneo. Las simulaciones de recarga elevada y baja causan un incremento de 0,05 m y un decremento de 0,025 m, respectivamente, en los niveles del acu

  11. Calcul et mesure de la température d'un plasma à l'aide des raies d'émission du cuivre

    NASA Astrophysics Data System (ADS)

    Sassi, M.; Pierre, L.; Bénard, J.; Cahen, C.

    1994-01-01

    The use of copper emission lines for temperature measurement in plasma environments is presented. The article features the problems encountered with such a measurement method when used in a stationnary and a non-stationnary plasma. In the first case, we were concerned with the temperature measurements in the jet of a 2MW industrial plasma torche. The plasma was stationnary and the measurement geometry allowed the use of the Abel inversion method to recover the temperature profiles in the plasma jet. The limitations of the measurement method on the jet boundaries as well as the cooling of the plasma by entrainement of cold air are discussed. In the second case, a non-stationnary plasma in a 1.4 MW electric furnace was studied. This study allowed to feature the role of the detector dynamics as related to the dynamics of the observed medium. The obtained measurements show only a probable temperature in the immediate proximity of the arc. Finally, we conclude on the validity of copper as a tracer and the use of spontaneous emission spectroscopy, an easy method to implement, compared to other sophisticated temperature measurement methods. L'utilisation des raies d'émission du cuivre pour la mesure de la température dans les plasmas est présentée. Cet article expose les problèmes posés par l'étude des températures dans les plasmas stationnaires et instationnaires. Dans le premier cas, on a été concerné par la mesure de la température dans le jet d'une torche à plasma industrielle (2 MW). Le plasma est stationnaire et la géométrie de la mesure permet l'inversion d'Abel pour remonter aux profils de température dans le jet. Les limitations de la méthode de mesure sur les bords du jet ainsi que le refroidissement du plasma par bouffées d'air froid sont discutés. Dans le second cas, un plasma instationnaire d'un four à arc (1,4 MW) a été étudié. Cette étude nous a permis de mettre en relief le rôle de la dynamique du détecteur et la façon de l

  12. Application of the groundwater-balance equation to indicate interbasin and vertical flow in two semi-arid drainage basins, Mexico

    NASA Astrophysics Data System (ADS)

    Carrillo-Rivera, J. J.

    2000-09-01

    conclusion est qu'une étude par bilan de la nappe est une méthode qui n'est pas satisfaisante pour déterminer certains paramètres comme le coefficient d'emmagasinement. En particulier, l'approche par le bilan de la nappe donne des résultats qui ne sont pas fiables lorsque l'on ignore la drainance verticale ou que l'on ne peut pas la définir correctement. L'existence d'une drainance verticale est prouvée par des températures de l'eau souterraine pouvant être supérieures de 23 °C à la température ambiante. Des failles régionales peuvent permettre ces écoulements vers le haut. Lorsque l'on ignore la drainance verticale, on introduit une incertitude sur l'estimation de l'emmagasinement à partir des calculs du bilan régional de la nappe. Sur la base de l'équation du bilan de la nappe, une valeur de S=0,19 semble représenter les conditions captives de la partie développée de l'aquifère ce résultat est plus élevé, de plusieurs ordres de grandeur, que celui que l'on peut raisonnablement attendre des conditions géologiques. Ces résultats sont utiles pour évaluer si une ressource en eau souterraine est "surexploitée". Ces conclusions sont intéressantes lorsque l'on applique des modèles d'écoulement transitoire dans lesquels on ne prend pas en compte la drainance verticale d'une eau plus légère remontant. Resumen. En este trabajo, se investigan las entradas y salidas de flujo horizontal en la ecuación de balance de agua subterránea, así como el papel que desempeñan en el flujo entre cuencas. Se analizan dos ejemplos de México, uno en la Península de Baja California y otro en la parte central del país. En ambos, destaca la influencia del flujo entre cuencas, ya que se estima que una parte importante (aproximadamente el 70%) del agua termal extraída procede de una cuenca superficial externa. Se concluye que el método basado en cálculos de balance de agua subterránea no es satisfactorio para determinar algunos parámetros, como, por ejemplo, el

  13. Hydrology of the coastal sabkhas of Abu Dhabi, United Arab Emirates

    NASA Astrophysics Data System (ADS)

    Sanford, Ward; Wood, Warren

    2001-05-01

    10 km de long et de 10 m d'épaisseur, indiquent qu'environ 1 m3/an d'eau entre et sort par écoulement souterrain latéral, que 40 à 50 m3/an entrent par drainance ascendante, et que 640 m3/an pénètrent par recharge à partir de la pluie. À partir des flux estimés d'eau et de solutés pour la drainance ascendante dans la sebkha, 7 à 8 volumes de pores de saumure sont entrés par en bas dans la sebkha depuis le moment où la sebkha est devenue saturée, il y a 7.000 ans, du fait de la dernière remontée du niveau marin. Resumen. Se ha estimado el flujo de agua y se ha efectuado un balance de agua en la superficie del terreno y en una sección superficial de 10 m de profundidad de los sabkhasAmbiente de sedimentación costera que se caracteriza por: (1) sus condiciones de aridez o semi-aridez por encima del nivel de mareas altas y (2) la ausencia de vegetación. Son habituales las evaporitas, depósitos eólicos y depósitos de inundación de marea. costeros cercanos a la ciudad de Abu Dhabi (Emiratos Árabes Unidos), al este de la frontera con Arabia Saudí. La estimación de los flujos se ha hecho con base en los niveles y conductividades hidráulicas medidos en pozos, y en las tasas de evaporación medidas mediante una cámara de humedad. Contrariamente a los modelos conceptuales propuestos en estudios previos, se ha estimado que la entrada de agua subterránea es pequeña, mientras que las componentes principales del balance son la recarga de agua de lluvia y la evaporación desde el nivel freático. Las estimaciones hechas en un volumen de sabkha de 1 m de anchura por 10 km de longitud y 10 m de profundidad indican que alrededor de 1 m3/a de agua entra y sale por flujo subterráneo lateral, 40-50 m3/a lo hacen por recarga desde niveles inferiores, y 650 m3/a proceden de la recarga de agua de lluvia. Teniendo en cuenta la estimación del flujo de agua y solutos para la recarga desde los niveles inferiores, se calcula que entre 7 y 8 vol

  14. Le point sur les amas de galaxies

    NASA Astrophysics Data System (ADS)

    Pierre, M.

    galaxies jouent donc un rôle de premier plan dans toute étude cosmologique et par conséquent, sont indispensables à notre compréhension globale de l'univers. Dans l'introduction générale, nous détaillons cet aspect fondamental en montrant comment l'étude des amas peut contribuer à contraindre les scénarios cosmologiques. Une fois le contexte scientifique délimité, les chapitres suivants s'attachent à présenter les diverses propriétés des amas et leur évolution cosmique observée dans diverses longueurs d'onde principalement dans les domaines visible (galaxies), X (gaz) et radio (gaz et particules). Nous verrons que l'étude détaillée d'un amas implique celle de l'interaction entre ses différentes composantes et est un passage obligé pour remonter au paramètre ultime (ou premier) qu'est sa masse. Loin d'être un détour ennuyeux, ceci sera l'occasion d'aborder des phénomènes physiques extrêmement variés tel l'aspect multi-phases du milieu intra-amas, les sursauts de formation d'étoiles et l'évolution morphologique des galaxies capturées par les amas, ou bien encore, l'interaction entre le plasma intra-amas et les particules relativistes accélérées lors de la fusion entre deux amas. Bien sûr, pour chaque longueur d'onde, nous ne manquerons pas de décrire simplement les techniques d'observation et d'analyse mises en oeuvre ; celles-ci sont particulièrement intéressantes dans le cas de l'instrumentation spatiale. Nous terminerons en présentant des projets d'observatoires pour l'horizon 2010 et leur impact prévu sur l'étude des amas de galaxies.

  15. Hydrology of the coastal sabkhas of Abu Dhabi, United Arab Emirates

    NASA Astrophysics Data System (ADS)

    Sanford, Ward; Wood, Warren

    2001-05-01

    10 km de long et de 10 m d'épaisseur, indiquent qu'environ 1 m3/an d'eau entre et sort par écoulement souterrain latéral, que 40 à 50 m3/an entrent par drainance ascendante, et que 640 m3/an pénètrent par recharge à partir de la pluie. À partir des flux estimés d'eau et de solutés pour la drainance ascendante dans la sebkha, 7 à 8 volumes de pores de saumure sont entrés par en bas dans la sebkha depuis le moment où la sebkha est devenue saturée, il y a 7.000 ans, du fait de la dernière remontée du niveau marin. Resumen. Se ha estimado el flujo de agua y se ha efectuado un balance de agua en la superficie del terreno y en una sección superficial de 10 m de profundidad de los sabkhasAmbiente de sedimentación costera que se caracteriza por: (1) sus condiciones de aridez o semi-aridez por encima del nivel de mareas altas y (2) la ausencia de vegetación. Son habituales las evaporitas, depósitos eólicos y depósitos de inundación de marea. costeros cercanos a la ciudad de Abu Dhabi (Emiratos Árabes Unidos), al este de la frontera con Arabia Saudí. La estimación de los flujos se ha hecho con base en los niveles y conductividades hidráulicas medidos en pozos, y en las tasas de evaporación medidas mediante una cámara de humedad. Contrariamente a los modelos conceptuales propuestos en estudios previos, se ha estimado que la entrada de agua subterránea es pequeña, mientras que las componentes principales del balance son la recarga de agua de lluvia y la evaporación desde el nivel freático. Las estimaciones hechas en un volumen de sabkha de 1 m de anchura por 10 km de longitud y 10 m de profundidad indican que alrededor de 1 m3/a de agua entra y sale por flujo subterráneo lateral, 40-50 m3/a lo hacen por recarga desde niveles inferiores, y 650 m3/a proceden de la recarga de agua de lluvia. Teniendo en cuenta la estimación del flujo de agua y solutos para la recarga desde los niveles inferiores, se calcula que entre 7 y 8 vol

  16. Etude des phenomenes dynamiques ultrarapides et des caracteristiques impulsionnelles d'emission terahertz du supraconducteur YBCO

    NASA Astrophysics Data System (ADS)

    Savard, Stephane

    Les premieres etudes d'antennes a base de supraconducteurs a haute temperature critique emettant une impulsion electromagnetique dont le contenu en frequence se situe dans le domaine terahertz remontent a 1996. Une antenne supraconductrice est formee d'un micro-pont d'une couche mince supraconductrice sur lequel un courant continu est applique. Un faisceau laser dans le visible est focalise sur le micro-pont et place le supraconducteur dans un etat hors-equilibre ou des paires sont brisees. Grace a la relaxation des quasiparticules en surplus et eventuellement de la reformation des paires supraconductrices, nous pouvons etudier la nature de la supraconductivite. L'analyse de la cinetique temporelle du champ electromagnetique emis par une telle antenne terahertz supraconductrice s'est averee utile pour decrire qualitativement les caracteristiques de celle-ci en fonction des parametres d'operation tels que le courant applique, la temperature et la puissance d'excitation. La comprehension de l'etat hors-equilibre est la cle pour comprendre le fonctionnement des antennes terahertz supraconductrices a haute temperature critique. Dans le but de comprendre ultimement cet etat hors-equilibre, nous avions besoin d'une methode et d'un modele pour extraire de facon plus systematique les proprietes intrinseques du materiau qui compose l'antenne terahertz a partir des caracteristiques d'emission de celle-ci. Nous avons developpe une procedure pour calibrer le spectrometre dans le domaine temporel en utilisant des antennes terahertz de GaAs bombarde aux protons H+ comme emetteur et detecteur. Une fois le montage calibre, nous y avons insere une antenne emettrice dipolaire de YBa 2Cu3O7-delta . Un modele avec des fonctions exponentielles de montee et de descente du signal est utilise pour lisser le spectre du champ electromagnetique de l'antenne de YBa 2Cu3O7-delta, ce qui nous permet d'extraire les proprietes intrinseques de ce dernier. Pour confirmer la validite du modele

  17. Effets perturbateurs endocriniens des pesticides organochlores.

    PubMed

    Charlier, C; Plomteux, G

    2002-01-01

    Xenoestrogens such organochlorine pesticides are known to induce changes in reproductive development, function or behaviour in wildlife. Because these compounds are able to modify the estrogens metabolism, or to compete with estradiol for binding to the estrogen receptor, it may be possible that these products affect the risk of developing impaired fertility, precocious puberty or some kinds of cancer in man. Le plus ancien récit de lutte contre la pollution remonte à une légende indienne racontant que la divinité Sing-bonga était incommodée par les émanations des fours dans lesquels les Asuras fondaient leurs métaux (1). Evidemment depuis, la problématique n-a cessé de s-accroître et la contamination de la Terre par de nombreux polluants est devenue aujourd-hui un problème majeur de notre Société. La protection de notre environnement est une question capitale qui doit être respectée malgré la pression économique actuelle et qui ne cessera de croître au cours des prochaines années même si l-identification objective et indiscutable de ce qui est essentiel - donc devant être prioritairement garanti sur la planète - est difficile à cerner (2). « Un oiseau en mauvais état ne pond pas de bons oeufs » disait un proverbe grec. Mais ce n-est qu-à partir de la seconde moitié du XXème siècle que les toxicologues ont commencé à identifier les effets qu-avaient entraînés à l-échelle mondiale les pollutions émises aux XIXème siècle sur la faune sauvage et sur le cheptel (3). L-histoire contemporaine des pesticides industriels commence vers 1874 (synthèse des organochlorés) et se poursuit tout au long de ces 2 siècles en passant par la synthèse des organophosphorés (1950), des carbamates (1970) et des pyréthroïdes (1975) (4). Le dichlorodiphényltrichloroéthane (DDT) a été synthétisé pour la première fois par un étudiant en cours de préparation de sa thèse de doctorat : Othmer Zeidler. La production, reprise par les

  18. Grid-based platform for training in Earth Observation

    NASA Astrophysics Data System (ADS)

    Petcu, Dana; Zaharie, Daniela; Panica, Silviu; Frincu, Marc; Neagul, Marian; Gorgan, Dorian; Stefanut, Teodor

    2010-05-01

    found in [4]. The Workload Management System (WMS) provides two types of resource managers. The first one will be based on Condor HTC and use Condor as a job manager for task dispatching and working nodes (for development purposes) while the second one will use GT4 GRAM (for production purposes). The WMS main component, the Grid Task Dispatcher (GTD), is responsible for the interaction with other internal services as the composition engine in order to facilitate access to the processing platform. Its main responsibilities are to receive tasks from the workflow engine or directly from user interface, to use a task description language (the ClassAd meta language in case of Condor HTC) for job units, to submit and check the status of jobs inside the workload management system and to retrieve job logs for debugging purposes. More details can be found in [4]. A particular component of the platform is eGLE, the eLearning environment. It provides the functionalities necessary to create the visual appearance of the lessons through the usage of visual containers like tools, patterns and templates. The teacher uses the platform for testing the already created lessons, as well as for developing new lesson resources, such as new images and workflows describing graph-based processing. The students execute the lessons or describe and experiment with new workflows or different data. The eGLE database includes several workflow-based lesson descriptions, teaching materials and lesson resources, selected satellite and spatial data. More details can be found in [5]. A first training event of using the platform was organized in September 2009 during 11th SYNASC symposium (links to the demos, testing interface, and exercises are available on project site [1]). The eGLE component was presented at 4th GPC conference in May 2009. Moreover, the functionality of the platform will be presented as demo in April 2010 at 5th EGEE User forum. References: [1] GiSHEO consortium, Project site, http

  19. Hydrodynamic characteristics of the western Doñana Region (area of El Abalario), Huelva, Spain

    NASA Astrophysics Data System (ADS)

    Trick, Thomas; Custodio, Emilio

    èle a été calé en utilisant d'une part les valeurs des paramètres hydrauliques obtenus par des essais de pompage et d'après les données piezométriques mesurées à différentes profondeurs, et d'autre part l'apport estimé de la ravine de La Rocina. L'écoulement d'eau souterraine s'effectue par drainage latérale dans trois directions, d'une part vers la côte, d'autre part à travers la ravine de La Rocina et finalement directement vers les Marais de Doñana situés à l'est et sud-est dans le delta du fleuve Guadalquivir. Avec une pluviométrie moyenne comprise entre 550 et 600 mm, la recharge nette moyenne annuelle des nappes, pour des périodes de temps assez longues, est estimée entre 100 et 200 mm dans les aires de végétation autochtone, et elle est nettement inférieure dans les aires plantées deucalyptus. Le modèle transitoire montre que la recharge varie dans l'espace et qu'elle n'est pas clairement proportionnelle aux précipitations annuelles. L'évapotranspiration phréatique joue un rôle important et diminue la valeur nette de la recharge des nappes de 0,4 à 0,6 de la valeur calculée avec un modèle de bilan d'eau dans le sol. La section modélisée est utilisée pour étudier l'effet de l'extraction d'eau souterraine sur la profondeur du niveau phréatique en soustrayant le flux vertical, calculé grâce à une formule d'hydraulique des puits, de la nappe profonde semi-confinée. Le résultat de cette extraction est une diminution de l'évapotranspiration phréatique, du flux au niveau de la ravine de La Rocina et de la fréquence d'inondation des lagunes. La substitution de forêts d'eucalyptus par de la végétation autochtone peut permettre la remonté des niveaux phréatiques et même réactiver d'anciens ravins affluents à La Rocina. La región de Doñana, situada en el sudoeste de España, incluye una gran e importante reserva natural, cuyos humedales están siendo afectados por la actividad humana. La extensa plantación de